阅读说明：本技术 一种涌水溃砂扰动深厚松散地层地面注浆成孔方法 (Water burst sand bursting disturbance deep unconsolidated formation ground grouting pore-forming method ) 是由 程桦 孙家应 姚直书 王志根 林健 荣传新 王晓健 宋海清 于 2020-06-22 设计创作，主要内容包括：本发明提供一种涌水溃砂扰动深厚松散地层地面注浆成孔方法,包括以下步骤：步骤S1,将地层划分为三段,三段地层分别为常规段、地层交替段、涌水溃砂段；步骤S2,对钻塔进行水平度校正及浇注水泥台,安装钻机并校准钻机的水平度和垂直度；步骤S3,对钻具进行改进,采用多级套管组成的宝塔式钻具进行组合钻孔,并采用套管环套+多级缩孔的方式进行钻孔和护孔；步骤S4,对步骤S1中的三段地层逐层进行钻进,形成钻孔；步骤S5,检测步骤S4中形成的钻孔的裂隙情况和胶结特性,并对钻孔进行清孔。本发明确保了煤矿立井井筒治理修复的正常进行,提高施工作业效率,降低了施工作业成本。(The invention provides a method for grouting and forming a hole on the ground of a gushing water and sand bursting disturbing deep unconsolidated formation, which comprises the following steps: step S1, dividing the stratum into three sections, wherein the three sections of the stratum are respectively a conventional section, a stratum alternating section and a water-inrush sand-bursting section; step S2, correcting the levelness of the drilling tower, pouring a cement platform, installing a drilling machine and calibrating the levelness and the verticality of the drilling machine; step S3, the drilling tool is improved, a pagoda type drilling tool consisting of multi-stage casing pipes is adopted for combined drilling, and drilling and hole protection are carried out in a casing pipe ring sleeve and multi-stage shrinkage hole mode; step S4, drilling the three sections of strata layer by layer in the step S1 to form drill holes; and step S5, detecting the fracture condition and the cementation characteristic of the drill hole formed in the step S4, and cleaning the drill hole. The method ensures the normal treatment and repair of the vertical shaft of the coal mine, improves the construction operation efficiency and reduces the construction operation cost.)

1. A water burst sand bursting disturbance deep unconsolidated formation ground grouting pore-forming method is characterized by comprising the following steps:

step S1, dividing the stratum into three sections, wherein the three sections of the stratum are respectively a conventional section, a stratum alternating section and a water-inrush sand-bursting section;

step S2, correcting the levelness of the drilling tower, pouring a cement platform, installing a drilling machine and calibrating the levelness and the verticality of the drilling machine;

step S3, the drilling tool is improved, a pagoda type drilling tool consisting of multi-stage casing pipes is adopted for combined drilling, and drilling and hole protection are carried out in a casing pipe ring sleeve and multi-stage shrinkage hole mode;

step S4, drilling the three sections of strata layer by layer in the step S1 to form drill holes;

and step S5, detecting the fracture condition and the cementation characteristic of the drill hole formed in the step S4, and cleaning the drill hole.

2. The method for grouting and forming holes on the ground of the gushing water and sand bursting disturbance deep unconsolidated formation according to claim 1, wherein the step S1 further comprises the step S101 of analyzing the formation soil parameters before grouting and then establishing the detection standard of the grouting effect of the vertical shaft treatment and restoration ground drilling:

a shaft with a depth less than 600m and a water leakage amount not more than 6m³/h；

A shaft with a depth of more than 600m and water leakage of less than 10m³/h；

Preferably, the basis for dividing the stratum in the step S1 is geological exploration report and geological properties;

still preferably, the water leakage of the water outlet point of the vertical shaft is not more than 0.5m³/h。

3. The method for grouting and forming the hole on the ground of the water burst sand-bursting deep unconsolidated formation according to claim 1, wherein the step S2 specifically comprises the following steps:

step S201, correcting the levelness of the drilling tower, pouring cement platforms at four corners of the drilling tower, correcting the levelness of the cement platforms to ensure that the cement platforms are in a horizontal state, and paving base wood on the cement platforms;

step S202, installing a drilling machine, and calibrating the levelness and the verticality of the drilling machine;

preferably, a leveling instrument is adopted for correcting the levelness of the cement platform;

still preferably, the levelness of the rig is controlled to ± 1%, and the control value for the levelness and verticality calibration of the drilling rig is 1%.

4. The method as claimed in claim 1, wherein the pagoda-type drilling tool in step S3 includes a drill bit and a multi-stage casing, the drill bit is a full-bore deviation-preventing drill bit composed of circular drill collars of different sizes, and the multi-stage casing is formed by connecting casings of multi-stage sizes;

the mode of the multi-stage sleeve ring sleeve is that the easily disturbed loose annular water layer is protected in time by using the overlapping ring sleeve of the two adjacent stages of sleeves, so that the water layer is prevented from collapsing.

5. The method for drilling holes on the ground by grouting and disturbing the deep unconsolidated formation through gushing water and sand crushing according to claim 1, wherein the drilling method for the conventional formation in the step S4 is as follows:

s401, drilling by adopting a primary drilling tool in a drill collar pressurization mode;

the drilling method for the alternating sections of the stratum in the step S4 is as follows:

step S402, in the range of the stratum interface and the soft-hard interbedded interface, a slight-pressure hanging drilling mode is adopted, the hole is rolled up and down, the drilling is carried out until the up-down resistance of a drilling tool is smaller than the initial resistance, the slurry consistency is increased, and the slurry flow is observed; after the stratum interface and the soft and hard interbed interface are passed through, a sleeve is immediately placed;

the drilling method for water burst sand bursting in the step S4 comprises the following steps:

and S403, when the sand layer is burst in gushing water, drilling in a light-pressure slow-turning mode, carrying out hole rolling up and down on the drilled hole, installing the casing pipe until the up-and-down resistance of the drilling tool is smaller than the initial resistance, then drilling, carrying out hole drilling inclination measurement after the hole rolling up is finished and the sand layer is burst in gushing water, replacing the drilling tool of the next stage for drilling, and protecting the hole by using the overlapped casing pipe so as to reduce the probability of repeatedly drilling and tamping the loose aquifer which is easy to disturb.

6. The method for forming holes on the ground by grouting water burst sand disturbance deep unconsolidated formation according to claim 5, wherein slurry is prepared for grouting in the drilling process of step S4, and the slurry level is not lower than the bottom of the casing all the time in the construction process of the drilling machine, so as to ensure the stability of the wall of the drilled hole;

preferably, the relative density of the prepared slurry is 1.2-1.3.

7. The method for grouting and forming the hole on the ground of the water burst sand-bursting deep unconsolidated formation according to claim 4, wherein the step S5 specifically comprises the following steps:

step S501, detecting the fracture condition and the cementation characteristic of the drilled hole after grouting;

step S502, after detection is finished, cleaning the drilled hole;

preferably, in the step S501, a borehole television is used for detection, and the grouting borehole and the observation borehole 10 are: 1, selecting holes;

still preferably, the relative density of the slurry used in the cleaning in step S502 is 1.0-1.05, and the density of the slurry at the bottom of the drilled hole is controlled to be 1.05-1.10.

8. The method for forming a hole by grouting on the surface of a deep unconsolidated formation disturbed by gushing water and collapsing sand according to claim 5, wherein in the step S401, the hole is measured once when 50m is drilled each time in the drilling process, so that the verticality of the drilled hole is ensured;

the position of the drilling mode of the light-pressure hoisting in the step S402 is within the range of 5m above and below the stratum interface and the soft-hard interbedded interface, the drilling distance of the upper and lower stripping holes is 1.5m, the upper and lower resistance of a drilling tool which drills after the upper and lower stripping holes is less than 30% of the initial resistance, and the flow rate of cement slurry is 35L/min;

in the step S403, the drilling position in a light-pressure slow-turning mode is 7-9m away from the water burst sand layer, the drilling distance of the upper and lower stripping holes is 0.5m, and the upper and lower resistance of the drilling tool for drilling after the upper and lower stripping holes is less than 20% of the initial resistance.

9. The method for drilling holes on the ground by grouting in the water burst sand-collapsing and disturbing the deep unconsolidated formation according to claim 3, wherein the abutment wood in the step S201 is a radial cross-grain wood block, and the density error and the size error of the abutment wood are respectively not more than 20% and not more than 5%;

the cement platform comprises two step bearing platform devices which are an upper step and a lower step respectively, and the cement platform is used for preventing the drilling machine from deflecting due to drilling load in the drilling process.

10. The method for forming the hole by grouting on the surface of the gushing water and sand bursting disturbing deep unconsolidated formation according to claim 1, wherein the multistage shrinkage in step S3 is implemented by drilling the hole with a small diameter in the next stage in a multistage shrinkage mode after passing through the first-stage disturbing layer, and sequentially passing through the disturbing layers.

Technical Field

The invention belongs to the technical field of vertical shaft treatment and restoration, and particularly relates to a method for forming a hole by grouting on the ground of a gushing water, sand bursting and disturbance deep unconsolidated formation.

Background

The ground drilling and grouting is a common method for controlling water damage in the process of coal mine vertical shaft construction and exploitation. The method improves the grouting of the broken and unstable surrounding rock encountered by a horizontal roadway or a vertical shaft by a ground drilling grouting method so as to improve the integrity of the surrounding rock and reduce the permeability of the surrounding rock, thereby achieving the purposes of improving the stability of the surrounding rock and reducing the supporting difficulty and ensuring the safe mining.

The ground grouting construction needs the mutual matching operation of drilling and grouting processes, and in the process of treating and repairing the vertical shaft of the coal mine, the disturbance condition of the stratum and the hydrogeological characteristics after disturbance are often found out through drilling, and the weak stratum is reinforced in a grouting mode, so the ground drilling grouting is gradually used for treating and repairing the vertical shaft. The coal mine vertical shaft is generally faced with complex weak strata for treating and repairing, so that the hole forming effect of drilling directly determines the success or failure of ground grouting construction.

In the process of treating and repairing a vertical shaft of a coal mine, a ground drilling surface faces a disturbed weak stratum which is easy to gush water and collapse sand, and a large amount of engineering practices show that although the drilling method of the weak stratum is greatly improved in the prior art, the phenomena of buried drilling and slurry leakage caused by serious stratum leakage often occur.

Therefore, the prior art shows great inadaptability in the face of gushing water and sand bursting stratum, and the problem of drilling, grouting and pore-forming on the ground of the gushing water and sand bursting stratum is very urgent, and an improved technical scheme aiming at the defects of the prior art needs to be provided.

Disclosure of Invention

The invention aims to provide a method for grouting and forming a hole on the ground of a gushing water and sand bursting disturbing deep and loose stratum, which is used for solving the problems of buried drilling, serious slurry leakage and easy deflection of a drill hole when the hole is formed on the ground of the gushing water and sand bursting stratum through grouting.

In order to achieve the above purpose, the invention provides the following technical scheme:

a water burst sand bursting disturbance deep unconsolidated formation ground grouting pore-forming method comprises the following steps:

step S1, dividing the stratum into three sections, wherein the three sections of the stratum are respectively a conventional section, a stratum alternating section and a water-inrush sand-bursting section;

step S2, correcting the levelness of the drilling tower, pouring a cement platform, installing a drilling machine and calibrating the levelness and the verticality of the drilling machine;

step S3, the drilling tool is improved, a pagoda type drilling tool consisting of multi-stage casing pipes is adopted for combined drilling, and drilling and hole protection are carried out in a casing pipe ring sleeve and multi-stage shrinkage hole mode;

step S4, drilling the three sections of strata layer by layer in the step S1 to form drill holes;

and step S5, detecting the fracture condition and the cementation characteristic of the drill hole formed in the step S4, and cleaning the drill hole.

As a preferable scheme, the step S1 further includes a step S101, where the parameters of the stratum soil body are analyzed before grouting, and then a detection standard of the grouting effect of the ground drilling for vertical shaft treatment and restoration is established as follows:

a shaft with a depth less than 600m and a water leakage amount not more than 6m³/h；

A shaft with a depth of more than 600m and water leakage of less than 10m³/h；

Preferably, the basis for dividing the stratum in the step S1 is geological exploration report and geological properties;

it is further preferredThe water leakage amount of the water outlet point of the vertical shaft is not more than 0.5m³/h。

As mentioned above, the method for forming a hole by grouting on the surface of the deep unconsolidated formation and disturbing by water burst and sand collapse includes, as a preferable scheme, the step S2 specifically including the following steps:

step S201, correcting the levelness of the drilling tower, pouring cement platforms at four corners of the drilling tower, correcting the levelness of the cement platforms to ensure that the cement platforms are in a horizontal state, and paving base wood on the cement platforms;

step S202, installing a drilling machine, and calibrating the levelness and the verticality of the drilling machine;

preferably, a leveling instrument is adopted for correcting the levelness of the cement platform;

still preferably, the levelness of the rig is controlled to ± 1%, and the control value for the levelness and verticality calibration of the drilling rig is 1%.

As a preferable scheme, the pagoda drilling tool in step S3 includes a drill bit and a casing, the drill bit is a full-hole anti-deviation drill bit composed of circular drill collars of different sizes, and the casing is a casing of multiple sizes connected by a circumferential ferrule;

the sleeve ring sleeving mode is that the overlapping ring sleeving of two adjacent layers of sleeves is utilized to timely protect the easily disturbed loose annular water layer, and the water layer is prevented from collapsing.

As mentioned above, the method for drilling a hole by grouting on the surface of a deep unconsolidated formation by disturbing gushing water and sand and breaking sand preferably includes the following steps:

s401, drilling by adopting a primary drilling tool in a drill collar pressurization mode;

the drilling method for the alternating sections of the stratum in the step S4 is as follows:

step S402, in the range of the stratum interface and the soft-hard interbedded interface, a slight-pressure hanging drilling mode is adopted, the hole is rolled up and down, the drilling is carried out until the up-down resistance of a drilling tool is smaller than the initial resistance, the slurry consistency is increased, and the slurry flow is observed; after the stratum interface and the soft and hard interbed interface are passed through, a sleeve is immediately placed;

the drilling method for water burst sand bursting in the step S4 comprises the following steps:

and S403, when the sand layer is burst in gushing water, drilling in a light-pressure slow-turning mode, carrying out hole rolling up and down on the drilled hole, installing the casing pipe until the up-and-down resistance of the drilling tool is smaller than the initial resistance, then drilling, carrying out hole drilling inclination measurement after the hole rolling up is finished and the sand layer is burst in gushing water, replacing the drilling tool of the next stage for drilling, and protecting the hole by using the overlapped casing pipe so as to reduce the probability of repeatedly drilling and tamping the loose aquifer which is easy to disturb.

According to the method for forming the hole by grouting on the ground of the water burst sand collapse disturbance deep loose stratum, as a preferred scheme, slurry is prepared in the drilling process of the step S4, the hole is formed by grouting, and the surface type of the slurry is not lower than the bottom of the sleeve in the construction process of a drilling machine, so that the stability of the wall of the drilled hole is ensured;

preferably, the relative density of the prepared slurry is 1.2-1.3.

As mentioned above, the method for forming a hole by grouting on the surface of the deep unconsolidated formation and disturbing by water burst and sand collapse includes, as a preferable scheme, the step S5 specifically including the following steps:

step S501, detecting the fracture condition and the cementation characteristic of the drilled hole after grouting;

step S502, after detection is finished, cleaning the drilled hole;

preferably, in the step S501, a borehole television is used for detection, and the grouting borehole and the observation borehole 10 are: 1, selecting holes;

still preferably, the relative density of the slurry used in the cleaning in step S502 is 1.0-1.05, and the density of the slurry at the bottom of the drilled hole is controlled to be 1.05-1.10.

As a preferable scheme, in the step S401, the hole measurement is performed once every 50m of drilling in the drilling process, so as to ensure the perpendicularity of the drilled hole;

the position of the drilling mode of the light-pressure hoisting in the step S402 is within the range of 5m above and below the stratum interface and the soft-hard interbedded interface, the drilling distance of the upper and lower stripping holes is 1.5m, the upper and lower resistance of a drilling tool which drills after the upper and lower stripping holes is less than 30% of the initial resistance, and the flow rate of cement slurry is 35L/min;

in the step S403, the drilling position by using the light-pressure slow-turning mode is 7-9m away from the water burst sand layer, the drilling distance of the upper and lower stripping holes is 0.5m, and the upper and lower resistance of the drilling tool for drilling after the upper and lower stripping holes is less than 20% of the initial resistance.

As the above-mentioned method for grouting and forming a hole on the ground of the water burst sand-bursting disturbing deep unconsolidated formation, as a preferred scheme, the base wood in the step S201 is a radial cross grain wood block, and the density error and the size error of the base wood are respectively no more than 20% and no more than 5%;

the cement platform comprises two step bearing platform devices which are an upper step and a lower step respectively, and the cement platform is used for preventing the drilling machine from deflecting due to drilling load in the drilling process.

As a preferable scheme, in the step S3, the multistage shrinkage cavity is specifically formed by drilling a small-diameter hole in the next stage in a multistage shrinkage cavity mode after passing through the first-stage disturbance layer, and the small-diameter hole passes through each stage of disturbance layer in sequence.

Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:

the ground pre-grouting hole forming method for the water-inrush sand-bursting stratum can better avoid the phenomena of buried drilling and slurry leakage caused by stratum leakage, and has better adaptability to the water-inrush sand-bursting stratum. In the invention, the stratum is subdivided into three stratums, and the qualified standard of grouting of each stratum is different, so that the targeted grouting can be accurately carried out according to the geological properties of the stratum. In addition, a mode of sleeve ring sleeve and multi-stage shrinkage hole is adopted during wall protection after drilling, so that the drilling of the aquifer which is easy to disturb can be protected more timely and effectively, and subsequent grouting is facilitated. The method ensures the normal treatment and repair of the vertical shaft of the coal mine, improves the construction operation efficiency and reduces the construction operation cost.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:

FIG. 1 is a schematic diagram illustrating a positional relationship between an upper step and a lower step according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a grouting hole forming process according to an embodiment of the present invention.

In the figure: 1. an upper step; 2. descending a step; 3. grouting a casing A; grouting a casing B; 4. grouting a casing C; 5. grouting a casing D; 6. and (7) grouting the sleeve E.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

As shown in fig. 1 and fig. 2, the invention provides a surface grouting pore-forming method for a water burst sand-collapsing disturbance deep unconsolidated formation, which comprises the following steps:

step S1, dividing the stratum into three sections, wherein the three sections of stratum are respectively a conventional section, a stratum alternating section and a water inrush sand bursting section, the step S1 further comprises a step S101, analyzing stratum soil parameters before grouting, wherein the soil parameters comprise the elastic modulus, the strength and the integrity of a soil body, and then establishing a detection standard for the grouting effect of the ground drilling for treating and repairing the vertical shaft, wherein the detection standard specifically comprises the following steps:

a shaft with a depth less than 600m and a water leakage amount not more than 6m³/h；

The depth of the shaft is more than 600m, and the water leakage amount is not more thanOver 10m³/h；

Preferably, the stratigraphic division in step S1 is based on geological survey reports and geological properties including aquifer sand, unconsolidated clay.

Preferably, the water leakage of the water outlet point of the vertical shaft is not more than 0.5m³/h。

Step S2, correcting the levelness of the drilling tower, pouring a cement platform, installing a drilling machine and calibrating the levelness and the verticality of the drilling machine, wherein the step S2 specifically comprises the following steps:

step S201, correcting the levelness of the drilling tower, pouring cement platforms at four corners of the drilling tower, correcting the levelness of the cement platforms to ensure that the cement platforms are in a horizontal state, and paving base wood on the cement platforms.

And S202, installing the drilling machine, and calibrating the levelness and the verticality of the drilling machine.

Preferably, a leveling instrument is adopted for correcting the levelness of the cement platform;

still preferably, the drilling tower is controlled to be at a levelness of ± 1%, and the control value for the levelness and verticality calibration of the drilling rig is 1%.

The base wood in the step S201 is a radial cross grain wood block, the density error of the base wood is not more than 20%, and the size error is not more than 5%.

As shown in fig. 1, the cement platform comprises two step bearing platform devices, wherein the two step bearing platform devices are an upper step 1 and a lower step 2 respectively, and the cement platform is used for preventing the drilling machine from deflecting due to drilling load in the drilling process. The size of the upper step 1 is 40m multiplied by 30m, the size of the lower step 2 is 50m multiplied by 50m, and the size of the lower step 2 is larger than that of the upper step 1, so that the base is more stable, and the materials of the upper step 1 and the lower step 2 are both cast by C30 concrete.

Step S3, improving the drilling tool, adopting a pagoda type drilling tool consisting of multi-stage casing pipes to carry out combined drilling, and adopting a casing pipe sleeve and multi-stage shrinkage hole mode to carry out drilling and hole protection, wherein the pagoda type drilling tool in the step S3 comprises a drill bit and the multi-stage casing pipes, the drill bit is a full-hole anti-deviation drill bit consisting of round drill collars with different sizes, and the multi-stage casing pipes are formed by connecting the casing pipes with multi-stage sizes; the multistage shrinkage cavity is characterized in that after the multistage shrinkage cavity passes through a first-stage disturbance layer, small-diameter drilling is carried out on the next stage in a multistage shrinkage cavity mode, and the small-diameter drilling passes through all stages of disturbance layers in sequence. The tower drilling tool is a full-hole anti-deviation drilling tool consisting of circular drill collars with different sizes, the lower part of the drilling tool adopts the drill collar with larger size, and the size of the drilling tool is gradually reduced from bottom to top. The multistage pagoda type drilling tool comprises three stages of casings, wherein the aperture of a first stage drill hole is 244.5mm, the aperture of a second stage drill hole is 177.8mm, and the aperture of a third stage drill hole is 139.7 mm.

As shown in fig. 2, the sleeve ring is used to protect the easily disturbed loose annular water layer in time by using the overlapping ring of two adjacent sleeves to prevent the water layer from collapsing. In the embodiment, when the casing wall protection is carried out, when the wall protection is carried out after the drilling, the inner wall of the drilling hole is protected by adopting the grouting casing pipe A3, the grouting casing pipe B4, the grouting casing pipe C4, the grouting casing pipe D5 and the grouting casing pipe E6, and the overlapping parts are arranged between the grouting casing pipe A3 and the grouting casing pipe B4, between the grouting casing pipe B4 and the grouting casing pipe C4, between the grouting casing pipe C4 and the grouting casing pipe D5, and between the grouting casing pipe D5 and the grouting casing pipe E6, so that the collapse of the aquifer can be better avoided, and the drilling hole which is easy to disturb the loose aquifer is timely protected.

Step S4, drilling the three sections of strata layer by layer in the step S1 to form drill holes, wherein the drilling method for the conventional strata in the step S4 is as follows:

and S401, drilling by adopting a primary drilling tool in a drill collar pressurization mode, and measuring the hole once every 50m during drilling in the step S401 so as to ensure the perpendicularity of the drilled hole.

The position of the drilling mode of the light-pressure hoisting in the step S402 is within 5m of the upper and lower stratum interfaces and the soft and hard interbedded interfaces, the drilling distance of the upper and lower stripping holes is 1.5m, the upper and lower resistance of a drilling tool which drills after the upper and lower stripping holes is less than 30% of the initial resistance, and the flow rate of cement slurry is 35L/min. And (3) within the range of 5m above and below the stratum interface and the soft and hard interbedded interface, carrying out slight-pressing hanging drilling in a manner of rolling up and down the drilled hole every time the drilled hole is drilled for 1.5m, carrying out drilling until the vertical resistance of the drilling tool is less than 30% of the initial resistance, increasing the consistency of the slurry, observing the flow of the slurry, wherein the flow of the cement slurry is 35L/min, and immediately placing a sleeve after the drilling tool passes through the stratum interface and the soft and hard interbedded interface.

In step S403, the drilling position by using the light-pressure slow-turning mode is 7-9m (e.g. 7m, 7.1m, 7.2m, 7.3m, 8m, 8.5m, 8.9m, 9m) away from the water burst sand layer, the drilling distance of the strip up and down holes is 0.5m, and the up and down resistance of the drilling tool drilling after strip up and down holes is less than 20% of the initial resistance. When the distance between the drilling tool and the water burst sand layer is about 8m, drilling is carried out in a light-pressure slow-turning mode, when the drilling is carried out for 0.5m, holes are rolled up and down on the drilled holes, the sleeve is installed when the up-and-down resistance of the drilling tool is smaller than 20% of the initial resistance, then the drilling is carried out, after the holes are rolled up, after the water burst sand layer passes through, the drilling hole inclination measurement is carried out, the drilling tool at the next stage is replaced for drilling, and the holes are protected by overlapping sleeves, so that the probability that the loose water-bearing layer is easy to disturb is repeatedly drilled and. The light pressure in the invention means that the bit pressure is relatively small, the hoisting is kept, the deviation of the vertical shaft is prevented, and the light pressure is generally adopted in a well section which is easy to generate well deviation. The light pressure slow turning means that the drilling mode is that the drilling mode starts to carry out low-vertical close striking with a stroke of 0.4-0.6 m (such as 0.4m, 0.42m, 0.43m, 0.48m, 0.5m, 0.55m, 0.58m and 0.6m) until the hole depth reaches 3-4 m (such as 3m, 3.1m, 3.2m, 3.3m, 3.5m, 3.6m, 3.9m and 4.m) below the casing, and then the stroke is increased to 1.0-1.5 m (such as 1.0m, 1.1m, 1.2m, 1.3m, 1.4m and 1.5m) to turn into normal continuous impact. The thickness of the steel plate of the pile casing is 8mm, the inner diameter of the pile casing is 100mm larger than the designed pile diameter, and two overflow holes are formed in the upper portion of the pile casing.

The drilling method for the alternating sections of the stratum in the step S4 is as follows:

step S402, in the range of the stratum interface and the soft and hard interbedded interface, a slight-pressure hoisting drilling mode is adopted, the hole is rolled up and down, the drilling is carried out until the up-and-down resistance of a drilling tool is smaller than that of the initial stage, the slurry consistency is increased, and the slurry flow is detected; and immediately placing the casing after the casing passes through the stratum interface and the soft and hard interbedded interface. In the grouting, the slurry is generally used from thin to thick, and the concentration of the slurry and the matching volume ratio of the two slurries are adjusted in time according to the large, medium and small slurry feeding amounts.

The drilling method for water burst sand bursting in the step S4 comprises the following steps:

and S403, when the sand layer is burst in gushing water, drilling in a light-pressure slow-turning mode, carrying out up-down hole rolling on the drilled hole, installing the casing pipe until the up-down resistance of the drilling tool is smaller than that of the initial stage, then drilling, carrying out drilling inclination measurement after the hole rolling is finished and the sand layer is burst in gushing water, replacing the drilling tool of the next stage for drilling, and protecting the hole by using the overlapped casing pipe so as to reduce the probability of repeatedly drilling and tamping the loose aquifer which is easy to disturb.

S4, preparing slurry for grouting to form a hole in the drilling process, wherein the slurry is not lower than the bottom of the casing in a surface mode in the construction process of the drilling machine and is used for ensuring the stability of the wall of the drilled hole;

preferably, the relative density of the formulated slurry is 1.2-1.3 (e.g., 1.21, 1.22, 1.23, 1.24, 1.25, 1.28, 1.29, 1.3). The grouting adopts superfine cement paste, the water cement ratio of the cement paste is controlled to be 0.65: 1, grouting by adopting a hydraulic grouting pump with the model of ZBYSB 100/20-18.5.

Step S5, observing the crack condition and the cementation characteristic of the drill hole formed in the step S4, and cleaning the drill hole, wherein the step S5 specifically comprises the following steps:

step S501, detecting the fracture condition and the cementation characteristic of the drilled hole after grouting;

step S502, after detection is finished, cleaning the drilled hole;

preferably, in the step S501, a borehole television is used for detection, and the grouting borehole and the detection borehole 10 are: 1, selecting holes;

still preferably, the relative density of the slurry used in the cleaning in step S502 is 1.0 to 1.05 (e.g., 1.0, 1.01, 1.02, 1.03, 1.04, 4.05), and the density of the slurry at the bottom of the borehole is controlled to be 1.05 to 1.10 (e.g., 1.05, 1.06, 1.07, 1.08, 1.09, 1.10). The cement-water glass double-liquid slurry has the advantages of controllable setting time within a few seconds to tens of minutes, high calculus rate (close to 100 percent) and quick early strength increase.

In conclusion, the ground pre-grouting hole forming method for the water-inrush sand-bursting stratum can better avoid the phenomena of buried drilling and slurry leakage caused by stratum leakage, and has better adaptability to the water-inrush sand-bursting stratum. In the invention, the stratum is subdivided into three stratums, and the qualified standard of grouting of each stratum is different, so that the targeted grouting can be accurately carried out according to the geological properties of the stratum. In addition, a mode of sleeve ring sleeve and multi-stage shrinkage hole is adopted during wall protection after drilling, so that the drilling of the aquifer which is easy to disturb can be protected more timely and effectively, and subsequent grouting is facilitated. The method ensures the normal treatment and repair of the vertical shaft of the coal mine, improves the construction operation efficiency and reduces the construction operation cost.

The above description is only exemplary of the invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and principle of the invention is intended to be covered by the appended claims.