阅读说明：本技术 堰塞体防渗墙成槽施工的预处理方法 (Pretreatment method for grooving construction of anti-seepage wall of dam plug body ) 是由 宗敦峰 肖恩尚 石峰 李明宇 肖瑞 丁冠杰 刘振国 于 2019-10-12 设计创作，主要内容包括：本发明公开了一种堰塞体防渗墙成槽施工的预处理方法,包括：在堰塞体的防渗墙轴线上,间隔钻设一排爆破孔；爆破孔钻设完成后,对爆破孔内遇到的孤石进行爆破处理,以便孤石被破碎成块石；孤石被破碎成块石后,在堰塞体防渗墙轴线的上游和下游,分别间隔钻设一排上游灌浆孔和一排下游灌浆孔；上游灌浆孔和下游灌浆孔钻设完成后,对灌浆孔进行灌浆处理,将堰塞体防渗墙轴线上游和下游的渗漏通道进行封堵,以便在地层完整、稳定的条件下进行堰塞体防渗墙的成槽施工。本发明的方法,可改善孤石多、架空现象严重、地层未经沉积和胶结的堰塞体的地质条件,利于后续在该地层上进行防渗墙施工。(The invention discloses a pretreatment method for grooving construction of a weir plug diaphragm cut-off wall, which comprises the following steps: drilling a row of blast holes at intervals on the axis of the impervious wall of the weir plug body; after the blast hole is drilled, blasting boulders encountered in the blast hole so as to break the boulders into lump stones; after the boulders are crushed into rock blocks, respectively drilling a row of upstream grouting holes and a row of downstream grouting holes at intervals at the upstream and the downstream of the axial line of the barrier body impervious wall; and after the upstream grouting hole and the downstream grouting hole are drilled, grouting treatment is carried out on the grouting holes, and the upstream leakage channel and the downstream leakage channel of the axial line of the barrier body diaphragm wall are plugged, so that the grooving construction of the barrier body diaphragm wall is carried out under the condition of complete and stable stratum. The method can improve the geological conditions of a weir plug body with a plurality of boulders, serious overhead phenomenon and undeposited and cemented stratum, and is beneficial to the subsequent construction of the impervious wall on the stratum.)

1. A pretreatment method for grooving construction of a barrier body diaphragm wall is characterized by comprising the following steps:

drilling a row of blast holes at intervals on the axis of the impervious wall of the weir plug body;

after the blast hole is drilled, blasting boulders encountered in the blast hole so as to break the boulders into lump stones;

after the boulders are crushed into rock blocks, respectively drilling a row of upstream grouting holes and a row of downstream grouting holes at intervals at the upstream and the downstream of the axial line of the barrier body impervious wall;

and after the upstream grouting hole and the downstream grouting hole are drilled, grouting treatment is carried out on the grouting holes, and the upstream leakage channel and the downstream leakage channel of the axial line of the barrier body diaphragm wall are plugged, so that the grooving construction of the barrier body diaphragm wall is carried out under the condition of complete and stable stratum.

2. The method of claim 1, wherein:

drilling a grouting hole by adopting a pneumatic down-the-hole drill pipe following drilling method or a geological drilling machine mud retaining wall rotary drilling method;

the grouting treatment of the grouting holes adopts a pipe-pulling grouting method or a perforated pipe grouting method.

3. The method of claim 2, wherein grouting the grout hole using a tube drawing grouting method comprises:

when the grouting hole is drilled to a preset depth, taking out the eccentric drill in the casing;

after the eccentric drill is taken out, lifting the casing pipe to form a grouting section with the length corresponding to the lifting depth of the casing pipe;

pouring grouting liquid at least comprising cement clay slurry into the grouting section by adopting a self-flow pouring method;

and after the bottom of the grouting section reaches the end standard, lifting the sleeve to continue grouting until the whole grouting hole is completely grouted.

4. The method of claim 2, wherein the grouting hole using a floral tube grouting method comprises:

when the grouting hole is drilled to a preset depth, taking out the eccentric drill in the casing;

after the eccentric drill is taken out, a perforated pipe with a grout outlet is arranged below the sleeve;

after the flower tube is completely arranged below the flower tube, the sleeve is taken out, and grouting liquid containing cement clay slurry is poured into the flower tube by adopting a hydraulic plug;

when grouting liquid is poured, the grouting liquid flows to the grouting holes and the adjacent unconsolidated strata through the grout outlet of the perforated pipe, and the grouting holes are grouted section by section from bottom to top.

5. The method as claimed in claim 3 or 4, wherein the step of grouting with a grouting liquid comprising cement clay slurry comprises the step of adjusting the water-solid ratio of the cement clay slurry in the grouting liquid at any time according to the grouting amount of the grouting liquid in the grouting hole.

6. The method of claim 5, wherein adjusting the water-to-solid ratio of the cement-clay slurry in the grout at any time according to the amount of grout in the grout hole comprises:

when the pouring amount of the grouting liquid in the grouting hole is less than 300kg/m, pouring by adopting the grouting liquid only containing cement clay slurry;

when the grouting amount of the grouting liquid in the grouting hole is more than 300kg/m and less than 2000kg/m, the grouting liquid comprising cement clay slurry and water glass is adopted for grouting.

7. The method of claim 1, wherein blasting the boulder encountered within the blast hole comprises:

in the process of drilling a blast hole, acquiring the position and size information of a boulder encountered in drilling;

and blasting the boulder according to the acquired position and size information of the boulder.

8. The method of claim 7, wherein blasting the boulder based on the acquired position and size information of the boulder comprises:

according to the position and size information of a plurality of boulders in each blast hole, the depth of the centers of the boulders in the blast hole is calculated, and the boulder size corresponding to the depth is marked;

and arranging explosive at the corresponding depth of the blast hole according to the size of the boulder so as to blast the boulder by the explosive.

9. The method of claim 8, wherein placing an explosive charge at a depth corresponding to the blast hole according to the size of the quarry stone, such that blasting the quarry stone with the explosive charge comprises:

determining the explosive quantity required for crushing each boulder according to the sizes of a plurality of boulders in the same blast hole;

binding explosives required for crushing a plurality of boulders according to the explosive quantity required for crushing each boulder;

and arranging the plurality of bound explosives to the corresponding boulder positions, and blasting.

10. The method of claim 9, wherein the banding of the explosive required to break the plurality of boulders based on the amount of explosive required to break each boulder comprises:

determining the number of sections of explosive required by each boulder according to the explosive quantity required by crushing each boulder;

according to the number of sections of explosive required by each boulder, bundling one end of the explosive according to a method of bundling four sections of explosive by using transparent adhesive tapes;

nylon ropes are used for binding explosives, and the bottoms of the nylon ropes are used as the centers of the first boulders at the bottoms of the blast holes for binding the explosives;

diffusing the explosive binding positions to the two ends of the center according to the size of the boulder;

after the binding position of the explosive is determined, placing a detonator in the bound explosive, winding and fixing a detonator line on a nylon rope, and secondarily fixing the explosive by using a transparent adhesive tape;

and taking the central position of the first boulder to be a reference, measuring the central position of the last boulder in the same blast hole, binding, and the like until the position of the orifice of the blast hole is measured and marked.

Technical Field

The invention relates to the field of hydraulic and hydroelectric engineering, in particular to a pretreatment method for grooving construction of a barrier plug body diaphragm wall.

Background

The damming body is formed by earthquake collapse and landslide, and because the damming lake remediation is in need, the damming body remediation needs to take the working ideas of simultaneous research, simultaneous design and simultaneous remediation, and needs to implement danger removal and flood control projects such as damming body remediation as soon as possible. The damming body renovation is to carry out anti-seepage treatment and partial slope renovation on the damming body, the damming base and the bank slope at two sides, and the damming body anti-seepage treatment adopts the combination of anti-seepage wall and curtain grouting.

For the dam body, the prior treatment engineering experience mainly aims at removing and dredging water flow, but for the dam body with huge volume formed by super-huge collapse, the removal cost is very high, and a proper field is difficult to find near an engineering address for piling so many piled bodies, so if the dam body can be fully utilized, the dam body is directly formed by utilizing the dam body, the harm and the benefit can be removed, and the waste is changed into the valuable. However, for the geological conditions of the dam body that the maximum depth of the impervious wall exceeds 130m, the thickness of the wall body exceeds 1.0m, the content of the boulder exceeds 50%, the maximum particle size of the boulder exceeds 15 m, the overhead phenomenon is serious, and the stratum is not deposited and cemented, the unfavorable conditions cause great difficulty for the construction of the impervious wall, great challenge is provided for the prior construction technology, how to enable the geological conditions of the dam body to form the geological conditions for the construction of the impervious wall can be realized, and no construction precedent exists at home and abroad in the longitudinal view.

Disclosure of Invention

The invention aims to overcome the problems in the prior art, and provides a pretreatment method for the grooving construction of the barrier body diaphragm wall, which can improve the geological conditions of the barrier body with more boulders, large particle size, serious overhead phenomenon, undeposited stratum and cemented stratum and is beneficial to the subsequent diaphragm wall construction on the stratum.

In order to achieve the above object of the present invention, the method for pretreating the damming body cut-off wall in grooving construction comprises:

drilling a row of blast holes at intervals on the axis of the impervious wall of the weir plug body;

after the blast hole is drilled, blasting boulders encountered in the blast hole so as to break the boulders into lump stones;

after the boulders are crushed into rock blocks, respectively drilling a row of upstream grouting holes and a row of downstream grouting holes with the depth of more than 70 meters at intervals on the upstream and downstream of the axis of the barrier body impervious wall;

and after the upstream grouting hole and the downstream grouting hole are drilled, grouting treatment is carried out on the grouting holes with the depth of more than 70 meters, and the upstream leakage channel and the downstream leakage channel of the axial line of the barrier body impervious wall are plugged, so that the grooving construction of the barrier body impervious wall is carried out under the condition of complete and stable stratum.

Wherein, drilling the grouting hole by adopting a pneumatic down-the-hole drill pipe-following drilling method or a geological drilling machine mud protection wall rotary drilling method; the grouting treatment of the grouting holes with the depth of more than 70 meters adopts a pipe-pulling grouting method or a perforated pipe grouting method.

Wherein, adopt the tube drawing grouting method to carry out the grout processing including to the grout hole that the degree of depth exceeds 70 meters:

when the grouting hole is drilled to a preset depth, taking out the eccentric drill in the casing;

after the eccentric drill is taken out, lifting the casing pipe to form a grouting section with the length corresponding to the lifting depth of the casing pipe;

pouring grouting liquid at least comprising cement clay slurry into the grouting section by adopting a self-flow pouring method;

and after the bottom of the grouting section reaches the end standard, lifting the sleeve to continue grouting until the whole grouting hole is completely grouted.

Wherein, adopting floral tube grouting method to carry out the grout treatment to the grout hole that the degree of depth exceeds 70 meters and including:

when the grouting hole is drilled to a preset depth, taking out the eccentric drill in the casing;

after the eccentric drill is taken out, a perforated pipe with a grout outlet is arranged below the sleeve;

after the flower tube is completely arranged below the flower tube, the sleeve is taken out, and grouting liquid containing cement clay slurry is poured into the flower tube by adopting a hydraulic plug;

when grouting liquid is poured, the grouting liquid flows to the grouting holes and the adjacent unconsolidated strata through the grout outlet of the perforated pipe, and the grouting holes are grouted section by section from bottom to top.

The grouting liquid containing cement clay slurry is adopted for grouting, and the step of adjusting the water-solid ratio of the cement clay slurry in the grouting liquid at any time according to the grouting amount of the grouting liquid in the grouting hole is included.

Wherein, according to the pouring amount of the grout in the grout hole, the step of adjusting the water-solid ratio of the cement-clay slurry in the grout at any time comprises the following steps:

when the pouring amount of the grouting liquid in the grouting hole is less than 300kg/m, pouring by adopting the grouting liquid only containing cement clay slurry;

when the grouting amount of the grouting liquid in the grouting hole is more than 300kg/m and less than 2000kg/m, the grouting liquid comprising cement clay slurry and water glass is adopted for grouting.

Wherein, blasting the boulder that meets in the blast hole includes:

in the process of drilling a blast hole, acquiring the position and size information of a boulder encountered in drilling;

and blasting the boulder according to the acquired position and size information of the boulder.

Wherein, according to the position and the size information of the boulder of obtaining, carry out blasting to the boulder and include:

according to the position and size information of a plurality of boulders in each blast hole, the depth of the centers of the boulders in the blast hole is calculated, and the boulder size corresponding to the depth is marked;

and arranging explosive at the corresponding depth of the blast hole according to the size of the boulder so as to blast the boulder by the explosive.

Wherein, according to the boulder size, corresponding degree of depth at the blast hole and settle the explosive to carry out blasting treatment to the boulder through the explosive and include:

determining the explosive quantity required for crushing each boulder according to the sizes of a plurality of boulders in the same blast hole;

binding explosives required for crushing a plurality of boulders according to the explosive quantity required for crushing each boulder;

and arranging the plurality of bound explosives to the corresponding boulder positions, and blasting.

Wherein, according to the required explosive amount of broken every boulder, carry out the ligature to the required explosive of broken a plurality of boulders and include:

determining the number of sections of explosive required by each boulder according to the explosive quantity required by crushing each boulder;

according to the number of sections of explosive required by each boulder, bundling one end of the explosive according to a method of bundling four sections of explosive by using transparent adhesive tapes;

nylon ropes are used for binding explosives, and the bottoms of the nylon ropes are used as the centers of the first boulders at the bottoms of the blast holes for binding the explosives;

diffusing the explosive binding positions to the two ends of the center according to the size of the boulder;

after the binding position of the explosive is determined, placing a detonator in the bound explosive, winding and fixing a detonator line on a nylon rope, and secondarily fixing the explosive by using a transparent adhesive tape;

and taking the central position of the first boulder to be a reference, measuring the central position of the last boulder in the same blast hole, binding, and the like until the position of the orifice of the blast hole is measured and marked.

Wherein, a plurality of explosives after will ligature are divided into and are set up to corresponding boulder position department, and it includes to carry out blasting treatment:

after the binding of the explosives matched with all the boulders in the same blast hole is finished, arranging the explosives in sequence from the sleeve arranged in the blast hole by using a suspension wire, and fixing the hole at the marked hole;

after the explosive is arranged below the explosive, the detonating cords of all detonators in the blasting hole are connected and led out to the detonator through the sleeve so as to carry out blasting treatment.

Wherein, on the axis of damming body cut-off wall, the interval is bored and is established a row of blast holes and includes:

drilling a row of blast holes on the axis of the barrier body impervious wall by adopting a method of pneumatic down-the-hole drilling pipe following drilling or rotary drilling of a mud protective wall of a geological drilling machine;

during the process of drilling the blast hole, when a fault or a fracture develops or a rock vein penetrates through a stratum, the drilling track, the drilling technical parameters and the drilling method are adjusted at any time according to the stratum so as to prevent the drilled hole from being bent.

During the process of drilling the blast hole, if pebbles are encountered, the drilling speed is slowed down, and the hole wall is repeatedly drilled and trimmed so as to ensure that the following pipe smoothly passes through the pebbles and avoid pipe blockage and casing pipe fracture.

Compared with the prior art, the pretreatment method for the grooving construction of the barrier body diaphragm wall has the beneficial effects that:

1. the method can transform the geological conditions of the barrier body of the impervious wall with the maximum depth of more than 130m, the wall thickness of more than 1.0m, the content of the boulder of more than 50 percent, the maximum particle size of the boulder of more than 15 meters, serious overhead phenomenon and undeposited and cemented stratum into the stratum with uniform, complete and stable stratum, is favorable for the subsequent construction of the impervious wall on the stratum, greatly reduces the risk of groove collapse caused by serious slurry leakage in the groove forming construction of the impervious wall and the condition that the groove forming efficiency is low due to the large boulder, ensures good construction quality and high construction efficiency, can enable the barrier lake to remove harm and benefit as soon as possible and change waste into valuable.

2. According to the method, before the construction of the impervious wall, the boulder in the range along the axis of the groove of the impervious wall is blasted, the boulder can be crushed into the lump stone, the stratum with high content of the original boulder is improved into the stratum with low content of the boulder, even the stratum without the boulder and only with small lump stones, the occurrence of the condition that the hole inclination exceeds the standard during the subsequent grooving and pore-forming of the impervious wall is effectively prevented, and the construction progress and quality of the impervious wall are ensured.

3. According to the method, before the construction of the impervious wall, grouting treatment is carried out on two sides of the axial line of the slot hole of the impervious wall, a large leakage channel is blocked, and a loose stratum is initially filled, so that the leakage situation during the construction of the impervious wall can be greatly reduced, and meanwhile, the integrity and the stability of the loose stratum are improved, so that the safe and smooth implementation of the construction of the impervious wall is ensured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Drawings

FIG. 1 is a schematic diagram showing the positions of a blast hole and upstream and downstream grouting holes in a pretreatment method for trenching construction of a weir plug body diaphragm wall;

FIG. 2 is a schematic illustration of the blast hole drilling and blasting process of the present invention;

FIG. 3 is a flow chart of the grouting hole grouting process of the present invention;

FIG. 4 is a schematic view of the present invention grouting a grouting hole by using a tube drawing method;

FIG. 5 is a schematic view of a floral tube of the present invention;

FIG. 6 is a diagram showing the ratio of grouting liquid used in grouting according to the present invention;

FIG. 7 is a flow chart of the pretreatment method for the grooving construction of the barrier diaphragm wall.

Detailed Description

The impervious system of the damming body renovation project is the core of the damming lake renovation project reservoir, and consists of a damming body impervious wall, left bank ancient landslide body curtain grouting and right bank bedrock curtain grouting. For the weir plug body with the depth of the impervious wall exceeding 100m and the maximum depth even exceeding 130m, the thickness of the wall exceeding 1.0m, the content of boulders exceeding 50%, the maximum particle size of the boulders exceeding 15 m, the overhead phenomenon is serious, and the geological conditions of stratum undeposited and cemented are extremely complex, in order to ensure the success of the construction of the impervious wall grooving, the invention pretreats the stratum before the construction of the impervious wall grooving, improves the geological conditions of the weir plug body in advance, and prevents slurry leakage and the occurrence of large boulders during the construction of the impervious wall grooving.

In order to achieve the above object, the present invention provides a method for pretreating a weir dam impervious wall in grooving construction, as shown in fig. 7, the method comprising:

drilling a row of blast holes at intervals on the axis of the impervious wall of the weir plug body;

after the blast hole is drilled, blasting boulders encountered in the blast hole so as to break the boulders into lump stones;

after the boulders are crushed into rock blocks, respectively drilling a row of upstream grouting holes and a row of downstream grouting holes with the depth of more than 70 meters at intervals on the upstream and downstream of the axis of the barrier body impervious wall;

and after the upstream grouting hole and the downstream grouting hole are drilled, grouting treatment is carried out on the grouting holes with the depth of more than 70 meters, and the upstream leakage channel and the downstream leakage channel of the axial line of the barrier body impervious wall are plugged, so that the grooving construction of the barrier body impervious wall is carried out under the condition of complete and stable stratum.

Specifically, the pretreatment method of the invention comprises the following steps:

s01, reforming the stratum with the content of the boulder exceeding 50 percent into a uniform stratum without the boulder

For the damming body with the boulder content exceeding 50% and the depth of the impervious wall exceeding 100 meters, the invention adopts the blasting method to carry out crushing treatment on a large amount of boulders: first, a blast hole for setting an explosive is drilled, and then, the boulder in the blast hole is crushed by the explosive.

S11 drilling a blast hole

In the invention, a row of blast holes (as shown in figure 1, the blast holes marked by YB in the figure) are drilled on the barrier body diaphragm wall axis at equal intervals, the interval between adjacent blast holes can be 1.2-1.6m, and the preferred embodiment is 1.5 m.

When drilling, according to the geological condition of site construction and the condition allowed by site equipment, drilling to the maximum depth so as to ensure the hole-forming quality of the impervious wall and the safety of the slotted hole as far as possible.

When a blast hole is drilled, the drilling method mainly adopts a pneumatic down-the-hole drill pipe following drilling method and can also adopt a geological drilling machine mud protection wall rotary drilling method, and the drilling principles of the two methods can refer to the prior art method and are not described in detail herein.

When the method of drilling with the pneumatic down-the-hole drill is adopted, the eccentric drill bit is adapted to the sleeve (as shown in a in figure 2), and the sleeve can be a high-quality geological steel pipe with the diameter of 114mm or 146 mm. The air compressor used should be adapted to the working air pressure of the down-the-hole hammer, and generally an air compressor with medium or high air pressure (not shown in the figure) is used.

All the blast holes drilled are vertical holes, and after the drilling machine is aligned with the hole positions, the mast or the vertical shaft of the drilling machine should be adjusted so that the drill rod and the sleeve pipe are kept in the vertical direction. In the drilling process, the perpendicularity of the casing pipe or the drill rod is required to be checked at any time, and problems are found and corrected in time. Particular attention should be paid to controlling the borehole deviation, especially for the upper 20m hole deviation, which requires no more than 1%.

All drilling holes are drilled according to strict operation requirements, so that accidents in the holes are avoided, the hole forming rate of the drilling holes is ensured, and metal objects such as casings and drilling tools cannot be abandoned in the holes.

The process flow when drilling the blast hole is as follows: hole aligning position → aligning drill → open hole → drilling with pipe → compressed air punching → adding drill rod, pipe with pipe → middle inclination testing → next cycle → final hole → hole testing.

When a blast hole is drilled, the hole inclination needs to be strictly controlled, otherwise, the blast cannot achieve the effect outside the impervious wall. In order to prevent the hole inclination of the drilled hole and ensure the verticality of the drilled hole, the invention adopts the following hole inclination ensuring measures:

(1) the foundation is solid and stable, the base platform is firm and regular, the installation of the drilling machine is regular, horizontal and stable, and the direction and the inclination angle of the vertical shaft meet the design requirements.

(2) In the stratum with fault, crack development and rock vein interpenetration, the drilled hole is easy to bend, and the drilling speed is not suitable to be adjusted too fast during drilling.

(3) According to the drilling condition, a field construction technician should timely follow the hole inclination measurement to know the drilling track;

(4) and reasonably determining drilling technical parameters according to the characteristics of the stratum, and selecting a drilling method.

(5) In order to ensure the verticality of the drilled hole, an eccentric hammer is selected for slow drilling in the hole drilling stage, an STL-1GW (antimagnetic wireless storage type digital gyro inclinometer) high-precision inclinometer can be used for hole inclination measurement control in the following pipe drilling stage, and the inclinometer is measured by a professional. The hole bottom slope should be no greater than 1%. During drilling with the pipe, the hole inclination within 20m is strictly controlled, the hole depth is 0-20 m, the measurement is carried out once every 5m, and if the drilling hole inclination exceeds the specification, the deviation is timely corrected.

In addition, the stratum change should be noticed at any time in the drilling process, when the cobble is drilled, the drilling speed should be slowed down, the hole wall should be drilled and trimmed repeatedly, the cobble is ensured to pass through smoothly along with the pipe, and the pipe is prevented from being blocked, so that the casing pipe is prevented from being broken. Meanwhile, the screw thread of the heel tube is subjected to enhanced inspection, the damaged screw thread needs to be replaced in time and is reprocessed, so that the screw thread in the hole is prevented from being broken and accidents in the hole are avoided.

Because the drilling equipment belongs to large-scale equipment and needs to be enhanced to maintain in use, the invention requires that the construction of a construction unit is suspended every 30 days, the equipment is forcibly checked and maintained, so that the equipment is always kept in a good state, and maintenance records of the sound large-scale equipment are established.

It should be noted that, because the requirement of the blast hole on hole inclination is extremely high, if the hole is inclined out of the range of the impervious wall, pre-blasting becomes meaningless, and the current down-the-hole drill construction can basically ensure that the hole is not inclined out of the impervious wall when the hole is constructed to 70m, but hardly ensures that the hole is inclined out of the impervious wall when the hole is more than 70m, so the blast hole construction can be carried out to about 70m deepest, and the boulder below 70m can be subjected to in-hole blasting treatment in the subsequent impervious wall construction process.

S12, crushing the boulder in the blast hole

When a high-frequency impactor is configured with a full-hydraulic drill to drill a blast hole along with a pipe, one-time drilling is performed to the bottom, in addition, in the drilling process, slag discharge and drilling conditions are closely observed, the number of boulders in the blast hole, the positions of the boulders and the sizes of the boulders are recorded in detail according to the drilling difficulty and the air return condition in the hole in the down-the-hole drilling process, and the positions of the boulders in the whole hole are sorted and labeled after the drilling is completed. And then, calculating the depth of the center of each boulder in the blast hole by taking the whole blast hole as a reference, and marking the size of the boulder corresponding to the depth. And finally, crushing each boulder in the blast hole.

After the blast hole is drilled and the position and size information of the corresponding boulder is determined, and before formal blasting construction of the boulder, the invention also needs to carry out a field simulation full-hole blasting test to determine the explosive quantity control parameter during blasting.

In the test, the diameter of the test boulder is properly determined according to the boulder with the approximately same diameter and the largest content in the stratum, and the test times can be determined according to the actual situation.

The invention passes through three times of field simulation full-hole blasting tests, and the test data are respectively as follows:

the first test: the drilling depth is 3m, the diameter of the maximum boulder is 1.0m, the total loading is 5.4Kg, and the average loading is 1.8 Kg/m;

and (3) second test: the drilling depth is 5m, the diameter of the maximum boulder is 2.0m, the total loading is 12.5Kg, and the average loading is 2.5 Kg/m;

for the third test: the drilling depth is 10m, the diameter of the maximum boulder is 3.0m, the total loading is 33Kg, and the average loading is 3.3 Kg/m.

After each field explosion is finished, excavation is immediately carried out, the explosion effect is visually checked, the boulder is broken into blocky stones and partial powder after the first two times of explosion, but the blocky stones still exist, and the boulder is broken into blocky stones with uniform sizes after the third time of explosion (the diameter of each blocky stone is between 5 and 50cm, the diameter is uniform, namely the number of the blocky stones with the same diameter is large), so that the loading capacity of the method can be controlled to be between 2 and 3kg/m according to specific geological conditions and field simulation test results, and is preferably 3 kg/m.

After the loading amount required by the boulder with a large crushing content is determined by the test method, each explosive is bound by using a transparent adhesive tape (only one end is bound and fixed) according to every four sections (1.2 kg in total), then, the explosive is bound by using a binding band with poor flexibility such as a nylon rope, the explosive is bound by using the bottom of the rope as the center of the first boulder at the bottom of the hole, and the binding position of the corresponding explosive is diffused to the two ends of the center according to the size of the first boulder. And after the binding position is determined, placing a detonator in the bound explosive, winding and fixing the detonator line on the nylon rope, and secondarily fixing the explosive by using a transparent adhesive tape. And taking out the center position of the upper boulder in the same blast hole according to the amount of the center position of the first boulder to be bound, and binding corresponding explosives according to the position, the size information and the corresponding explosive quantity of each boulder obtained originally by analogy until the orifice position of the blast hole is measured, and marking.

After the binding of all explosives in the whole blast hole is finished, arranging the explosives below the PVC pipe which is arranged in advance through the suspension wire, binding and fixing the suspension wire at the marked orifice position, after the binding is finished, leading out the detonating cord of the blast hole to the detonator, and performing blasting construction after the safety warning is finished.

It should be noted that, for the individual boulders with the maximum particle size exceeding 10m, the loading amount needs to be increased appropriately, and in addition, the boulders can be crushed by adopting a separate loading blasting method during the process of forming the impervious wall groove. Of course, if the boulder with the diameter less than 1 meter is encountered, the loading amount can be also reduced properly.

The processing of the boulders in all blast holes can be carried out according to the method, and the detailed description is omitted.

Before the construction of the impervious wall, a row of blast holes are drilled along the axis of the slot hole of the impervious wall, all boulders in the blast holes are blasted, and the boulders are crushed into small boulders, so that the original stratum with high boulder content is improved into a stratum with low boulder content, even without boulders and only with uniform small boulders, the situations of hole inclination exceeding standard and low grooving efficiency when the large boulders cause the subsequent grooving and hole forming of the impervious wall are effectively prevented, and the construction progress and quality of the impervious wall are ensured.

S02, reforming the loose and overhead stratum into a stable and complete stratum

After the boulder is crushed by the blasting method, the stratum has no more boulder, but the original stratum is looser, and the stratum after blasting is looser, so that the stratum is leveled by drilling grouting holes and grouting the unconsolidated stratum through the grouting holes as shown in fig. 3 in order to improve the integrity and stability of the unconsolidated stratum.

S21 drilling grouting holes

After the boulders are crushed into uniform stones, a row of upstream grouting holes (holes marked as YGS in figure 1) and a row of downstream grouting holes (holes marked as YGX in figure 1) with the depth of more than 70 meters are drilled at intervals respectively at the upstream and the downstream of the axis of the barrier body impervious wall, namely at the two sides of the axis of the barrier body impervious wall. The distance between the grouting holes and the axis of the impervious wall is 0.9m, the row spacing between the upstream grouting hole and the downstream grouting hole is 1.8m, and the hole spacing is 2.0 m. Wherein, the row pitch refers to the distance along the water flow direction, and the hole pitch refers to the distance perpendicular to the water flow direction.

When drilling, according to the geological condition of site construction and the condition allowed by site equipment, drilling to the maximum depth (at least more than 70 meters) so as to ensure the hole-forming quality of the impervious wall and the safety of the slotted hole as far as possible. The drilling method of the grouting hole can adopt the method of the pneumatic down-the-hole drill pipe following drilling of the blast hole, and can also adopt the method of the geological drilling machine mud retaining wall rotary drilling, and the details are not repeated.

It should be noted that, during the process of drilling the grouting holes, the upstream grouting holes and the downstream grouting holes should be arranged in a triangle, that is, as shown in fig. 1, from the hole site layout diagram of the blast holes and the grouting holes, one downstream grouting hole is located between two upstream grouting holes, and one upstream grouting hole is located between two downstream grouting holes. The upstream grouting holes and the downstream grouting holes are arranged in a triangular shape, so that grouting liquid can fully flow into loose formations on two sides of the impervious wall during grouting.

S22, grouting into the grouting hole

And after the upstream grouting hole and the downstream grouting hole are drilled, grouting the upstream grouting hole and the downstream grouting hole by adopting a pipe drawing grouting method.

The process of grouting each grouting hole by using the pipe drawing grouting method can be as shown in fig. 4(a-e), and comprises the following steps;

when the grouting hole is drilled to a preset depth (shown as a in figure 4), taking out the eccentric drill in the casing (shown as b in figure 4);

after the eccentric drill is taken out, the casing is lifted to form a grout section having a length corresponding to the lifting depth of the casing (as shown by c in fig. 4, the height is lifted by 1 meter to be the length of the grout section);

pouring grouting liquid at least comprising cement clay slurry into the grouting section by adopting a self-flow pouring method (as shown by d in figure 4);

after the bottom of the grouting section reaches the end standard, the casing is lifted (as shown by e in fig. 4, the height is lifted by 1 meter to be used as the length of the grouting section), and grouting is continued in the above manner until the whole grouting hole is completely grouted.

Or after the upstream grouting hole and the downstream grouting hole are drilled, grouting treatment can be carried out on the upstream grouting hole and the downstream grouting hole by adopting a perforated pipe grouting method, and the method comprises the following steps:

when the grouting hole is drilled to a preset depth, taking out the eccentric drill in the casing;

after the eccentric drill is taken out, a perforated pipe with a grout outlet is arranged below the sleeve;

after the flower tube is completely arranged below the flower tube, the sleeve is taken out, and grouting liquid containing cement clay slurry is poured into the flower tube by adopting a hydraulic plug;

when grouting liquid is poured, the grouting liquid flows to the grouting holes and the adjacent unconsolidated strata through the grout outlet of the perforated pipe, and the grouting holes are grouted section by section from bottom to top.

When the perforated pipe is adopted for grouting, the structure diagram of the perforated pipe is shown in fig. 5, a PVC perforated pipe is adopted, the diameter of the perforated pipe is phi 89mm, each circle of grout outlet holes are drilled at every 0.5m on the outer wall of the perforated pipe, each circle of grout outlet holes comprises 3 grout outlet holes (namely, the grout outlet holes are spaced at 120 degrees along the circumferential direction of the perforated pipe), the aperture of each grout outlet hole can be 1.5cm, and the grout outlet holes are sealed by using adhesive tapes. The length of every section floral tube can be 3.0 ~ 6.0m, connects between the adjacent floral tube, connects and to adopt prior art connected mode, adjusts according to the construction conditions, nevertheless will ensure to set up the floral tube when can not loosen and take off. After the floral tube is completely arranged below the floral tube, the sleeve is pulled out by using a tube drawing machine, and the PVC floral tube is left in the drilled grouting hole so as to be grouted section by section from bottom to top by adopting a hydraulic plug.

Regardless of the grouting method, a method of simultaneously grouting through a plurality of grouting holes or a method of grouting through a single grouting hole may be used in grouting.

The grouting liquid at least comprising cement clay slurry is cement clay slurry, the water-solid ratio is 0.7:1 and 0.4:1, and 5% or 10% of water glass is added into the grouting liquid with the water-solid ratio of 0.4:1 for grouting if necessary, so that the consistency of the grouting liquid is increased, the setting time of the grouting liquid is accelerated, the setting time of the grouting liquid is controlled, the diffusion range of the grouting liquid is controlled, the grouting is controllable, grouting materials can be saved, and a leakage channel can be effectively blocked.

The slurry preparation adopts a ZJ-400 type stirrer, and the concrete pulping is carried out according to the following procedures: pulping: adding water, adding cement, stirring, adding slurry, and stirring for 2 min; the cement clay slurry can be used after being expanded for 4-6 hours under the condition, and can be directly used under the condition; after the cement clay slurry is produced, it is passed through a screen to remove large particles, and then fed into a slurry tank, in which a perforated pipe is placed, and the slurry in the tank is pumped or stirred by high-pressure air so as to make it be in uniform state.

During grouting, the water-solid ratio of cement clay slurry in grouting liquid is adjusted at any time according to the grouting amount of the grouting liquid in a grouting hole and the grouting coefficient Q/P (Q is the grouting flow and P is the grouting pressure):

when the grouting amount of grouting liquid in the grouting hole is less than 200kg/m, the grouting liquid is cement clay slurry with the water-solid ratio of 0.7:1, and the grouting liquid comprises the following components: cement, clay and water, wherein the weight ratio of the cement to the clay to the water is 1: 1: 1.4;

when cement clay slurry with a water-solid ratio of 0.7:1 is adopted for grouting and the groutability coefficient Q/P is basically unchanged, the pouring amount of grouting liquid is increased to ensure that the pouring amount of the grouting liquid is more than or equal to 200kg/m and less than 300kg/m, and the grouting liquid adopts the cement clay slurry with the water-solid ratio of 0.4:1, and the method comprises the following steps: cement, clay and water, wherein the weight ratio of the cement to the clay to the water is 1: 1: 0.8;

when cement clay slurry with a water-solid ratio of 0.4:1 is adopted for grouting and the groutability coefficient Q/P is basically unchanged, the pouring amount of grouting liquid is increased to enable the pouring amount of the grouting liquid to be larger than or equal to 300kg/m and smaller than 1000kg/m, and at the moment, 5% of water glass is doped in the cement clay slurry with the water-solid ratio of 0.4:1, wherein the cement clay slurry comprises: cement, clay and water, wherein the weight ratio of the cement to the clay to the water is 1: 1: 0.8, and the weight ratio of the cement clay slurry to the water glass is 1: 0.05;

when cement clay slurry with a water-solid ratio of 0.4:1 and grouting liquid doped with 5% of water glass are adopted for grouting and the groutability coefficient Q/P is basically unchanged, the grouting amount of the grouting liquid is increased to enable the grouting liquid to be poured in an amount which is more than or equal to 1000kg/m and less than 2000kg/m, and at the moment, the grouting liquid is prepared by doping 10% of water glass into the cement clay slurry with the water-solid ratio of 0.4:1, wherein the cement clay slurry comprises: cement, clay and water, wherein the weight ratio of the cement to the clay to the water is 1: 1: 0.8, and the weight ratio of the cement clay slurry to the water glass is 1: 0.1;

when the grouting amount of the grouting liquid in the grouting hole is more than or equal to 2000kg/m, the grouting of the section can be finished; or when the grouting pressure reaches more than 0.5Mpa and the grouting injection rate is still low (less than 10L/min), the grouting of the section can be finished.

In addition, when grout is poured, the grouting pressure is adjusted at any time according to the grout consumption in the grouting hole, generally, the grouting pressure is 0.2-0.5 Mpa, when the grout consumption is large, the grouting pressure is low, and when the grout consumption is small, the grouting pressure is high.

It should be noted that, for a stratum which is found to have more solitary rock content, larger particle size and more serious stratum overhead condition through geological data and exploration hole analysis, grouting must be performed according to the above finishing standard, and for each grouting hole close to the bedrock, the adjacent hole pitch in the upstream row of grouting holes is encrypted, for example, the original hole pitch is encrypted from 2m to 1m to 1.5m, and the unit consumption of grouting is adjusted, generally, the unit consumption is 1500-2000 Kg/m.

In addition, in the actual construction process, grouting and finishing standards and the like can be adjusted according to the actual conditions of the stratum:

for example, for a grouting hole close to an ancient landslide body, when the grouting amount of grout in the hole is less than 200kg/m, the grouting can be performed by adopting cement clay grout with the water-solid ratio of 0.7:1, when the grouting amount is more than or equal to 200kg/m, the grouting can be performed by adopting more concentrated grout, such as cement clay grout with the water-solid ratio of 0.4:1, and when the grouting amount is more than or equal to 300kg/m, the grouting of the section can be finished.

The method has the advantages that by grouting the stratum before grooving construction of the barrier dam body, the leakage passages at the upstream and the downstream of the axis of the barrier dam body barrier dam wall can be plugged, so that grooving construction of the barrier dam body barrier dam wall is carried out under the condition that the stratum is complete and stable.

Of course, during specific construction, the grouting process and the blasting process can be alternatively constructed according to the influence of a working face.

Once severe slurry leakage and hole collapse occur in the construction of the barrier plug impervious wall, the groove section is possibly backfilled, so that the construction period is delayed, and the economic loss is huge, but by adopting the method disclosed by the invention, the stratum before the grooving construction is performed is subjected to blasting treatment (namely pre-blasting), large boulders in the stratum can be completely blasted to form small boulders, the stratum is subjected to grouting treatment (namely pre-grouting) in advance, a leakage channel can be plugged in advance, the stratum cementation is also well improved, the stability of damaged and loose accumulation bodies around the groove holes is greatly improved, the slurry leakage and hole collapse in the subsequent grooving construction of the impervious wall are greatly reduced, the construction period is shortened, the progress and the quality of the grooving construction of the impervious wall are ensured exactly, the direct economic cost of handling accidents is saved, and the economic benefit is obvious.

Although the present invention has been described in detail, the present invention is not limited thereto, and those skilled in the art can modify the principle of the present invention, and thus, various modifications made in accordance with the principle of the present invention should be understood to fall within the scope of the present invention.