阅读说明：本技术 一种地下连续墙施工方法 (Underground continuous wall construction method ) 是由 王歌 张健 席义泉 于 2019-10-19 设计创作，主要内容包括：本发明公开了一种地下连续墙施工方法,包括如下步骤：施工准备；成槽施工；钢筋笼制作及吊放；混凝土灌注成型；接头箱顶拔；下方钢筋笼时先安装所述接头箱,且安装接头箱前向槽中回填3-5m高的回填土,在浇筑混凝土时预留一块自然养护的混凝土试块,根据混凝土试块的凝固时间控制接头箱顶拔的时间和速度,具体操作方法为：浇注砼时应做好自然养护试块,正式开始顶拔接头箱的时间应等于自然养护试块达到终凝状态所经历的时间,开始第一次顶拔之后以后每30min提升一次,每次50~100cm,直至连续墙最上面部分混凝土终凝时将接头箱完全拔出。在地下连续墙施工过程中能够保证成槽的尽量垂直,同时接头衔接时对于接头箱的安装和顶拔也能起到良好的效果。(The invention discloses a construction method of an underground continuous wall, which comprises the following steps of construction preparation, grooving construction, reinforcement cage manufacturing and hoisting, concrete pouring and molding, joint box jacking, wherein the joint box is firstly installed when the lower reinforcement cage is installed, backfill with the height of 3-5m is backfilled in a groove before the joint box is installed, a naturally cured concrete test block is reserved when concrete is poured, the jacking time and speed of the joint box are controlled according to the solidification time of the concrete test block, the concrete operation method is that the naturally cured test block is prepared when the concrete is poured, the formal jacking time of the joint box is equal to the time of the naturally cured test block reaching a final set state, the joint box is lifted every 30min after the first jacking is started, and the joint box is completely pulled out every time of 50 ~ 100cm until the uppermost part of the concrete of the continuous wall is finally set, the grooving can be ensured to be vertical as much as possible in the construction process of the underground continuous wall, and good effects on the installation and jacking of the joint box can be achieved when the joint is connected.)

1. A construction method of an underground diaphragm wall is characterized by comprising the following steps: firstly, construction preparation, site cleaning, paying-off measurement, construction of a guide wall and slurry prefabrication; step two, grooving construction; step three, manufacturing and hoisting a reinforcement cage; step four, pouring and forming concrete; fifthly, jacking and pulling the joint box;

firstly installing the joint box when the reinforcement cage below the step three is installed, backfilling 3-5m high back filling soil into the groove before the joint box is installed, reserving a naturally cured concrete test block when concrete is poured, and controlling the time and speed of jacking and pulling the joint box according to the solidification time of the concrete test block, wherein the specific operation method comprises the following steps of:

and (3) preparing a natural maintenance test block when pouring concrete, formally starting to jack and pull the joint box, wherein the time for formally starting to jack and pull the joint box is equal to the time for the natural maintenance test block to reach a final set state, and the joint box is lifted every 30min after the first jacking, and is lifted by 50 ~ 100cm each time until the concrete at the uppermost part of the continuous wall is finally set.

2. A method of constructing an underground diaphragm wall according to claim 1, wherein: when the guide wall is manufactured in the first step, the guide wall is of an integral reinforced concrete structure, the net width of the guide wall is 5cm thicker than that of the underground continuous wall, the top opening of the guide wall is flat with the ground, the guide wall must be inserted into undisturbed soil, and the top surface of the guide wall is higher than the underground water level by more than 1.5 m.

3. A method of constructing an underground diaphragm wall according to claim 1, wherein: during grooving construction in the second step, for construction in a single unit groove section, single holes at two ends of the groove section are firstly dug according to the sequence of firstly digging two sides and then digging the middle, or a method of digging a first hole, then jumping for a distance and then digging a second hole is adopted, so that a partition wall is formed between the two single holes.

4. A method of constructing an underground diaphragm wall according to claim 3, wherein: after the single hole and the hole partition wall are dug to the designed depth, the grab bucket is sleeved and dug along the length direction of the groove, concave and convex surfaces formed due to different verticality of the grab bucket forming the groove are repaired to be smooth when the grab bucket digs the single hole and the partition wall, and when the grab bucket is sleeved and dug along the length direction of the groove, the grab bucket is lowered to the groove section designed depth to remove the bottom sediment of the groove.

5. The underground diaphragm wall construction method according to claim 4, wherein: during grooving, the corner of the guide wall is correspondingly placed by about 20cm according to the shape of the end face of the grooving machine.

6. A method of constructing an underground diaphragm wall according to claim 1, wherein: and step three, when the steel bars are manufactured, the steel bars are manufactured on a horizontal and flat operation interface.

7. A method of constructing an underground diaphragm wall according to claim 1, wherein: and step four, when concrete is poured, simultaneously pouring by using two guide pipes in the same groove section, wherein the distance between the two guide pipes is less than 3m, the distance between the guide pipes and a groove section joint is less than 1.5m, the concrete surfaces corresponding to the two pouring points uniformly rise during pouring, the height difference of the concrete surface at each guide pipe is less than 0.5m, and the pouring is completed before the final setting of the concrete.

Technical Field

The invention relates to foundation engineering, in particular to a construction method of an underground diaphragm wall.

Background

The underground diaphragm wall is a common foundation treatment method, not only can play a powerful supporting role, but also has the effect of water stopping and water preventing at intervals, is suitable for most soil bodies, and is widely applied to the field of buildings.

The construction of general underground continuous wall all needs to pass through the process of grooving, often for spacing grooving when forming the groove, just can guarantee that the region of pouring at every turn is less, and the risk is controllable, and can involve the linking problem between the groove section of both ends during the grooving of second round, and the processing of joint department is crucial, and it has directly decided underground continuous wall's stagnant water effect and seepage prevention performance, therefore especially pays attention to the junction between the groove section in the work progress. In the prior art, joint boxes are basically installed at two ends of a groove after the groove is formed, and vertically installed I-shaped steel exists at the end part of a groove section which is poured, so that the problem of jacking and pulling of the joint boxes after pouring is solved for foundation engineering with large depth. The area of contact with the I-steel is great on the one hand, and the jacking degree of difficulty is great, and on the other hand is difficult to control whether the concrete is moulded and can not fill the joint region that the joint case occupied originally when drawing, and if the too late of drawing then the concrete of pouring can solidify the joint case and be difficult to pull out.

Disclosure of Invention

In view of the disadvantages of the prior art, the present invention provides a method for constructing an underground diaphragm wall, which facilitates the smooth extraction of a joint box and maintains a sufficient overlapping area between adjacent groove sections.

The technical purpose of the invention is realized by the following technical scheme: a construction method of an underground diaphragm wall is characterized by comprising the following steps: firstly, construction preparation, site cleaning, paying-off measurement, construction of a guide wall and slurry prefabrication; step two, grooving construction; step three, manufacturing and hoisting a reinforcement cage; step four, pouring and forming concrete; fifthly, jacking and pulling the joint box;

firstly installing the joint box when the reinforcement cage below the step three is installed, backfilling 3-5m high back filling soil into the groove before the joint box is installed, reserving a naturally cured concrete test block when concrete is poured, and controlling the time and speed of jacking and pulling the joint box according to the solidification time of the concrete test block, wherein the specific operation method comprises the following steps of:

and (3) preparing a natural maintenance test block when pouring concrete, formally starting to jack and pull the joint box, wherein the time for formally starting to jack and pull the joint box is equal to the time for the natural maintenance test block to reach a final set state, and the joint box is lifted every 30min after the first jacking, and is lifted by 50 ~ 100cm each time until the concrete at the uppermost part of the continuous wall is finally set.

Through adopting above-mentioned technical scheme, can guarantee the perpendicular as far as possible of grooving in underground continuous wall work progress, also can play good effect to the installation and the top-lift of joint case when the joint links up simultaneously, also can guarantee to connect and can reserve sufficient joint region after the case top-lift simultaneously.

The invention is further provided with: when the guide wall is manufactured in the first step, the guide wall is of an integral reinforced concrete structure, the net width of the guide wall is 5cm thicker than that of the underground continuous wall, the top opening of the guide wall is flat with the ground, the guide wall must be inserted into undisturbed soil, and the top surface of the guide wall is higher than the underground water level by more than 1.5 m.

By adopting the technical scheme, the liquid level of the slurry in the groove section during groove forming can be effectively controlled only when the liquid level of the slurry is about 1.5m higher than the underground water level, so that the top surface of the guide wall is required to be 1.5m higher than the underground water level during manufacturing of the guide wall, and if the local height difference is insufficient, measures for increasing the specific gravity of the slurry or measures for reducing the water can be taken, thereby being beneficial to improving the stability of the groove wall after groove forming.

The invention is further provided with: during grooving construction in the second step, for construction in a single unit groove section, single holes at two ends of the groove section are firstly dug according to the sequence of firstly digging two sides and then digging the middle, or a method of digging a first hole, then jumping for a distance and then digging a second hole is adopted, so that a partition wall is formed between the two single holes.

By adopting the technical scheme, the single holes at the two ends of the groove section are dug firstly, or the method of digging the second hole after the first hole is dug and jumping for a certain distance is adopted, so that the partition wall which is not dug is left between the two single holes, the grab bucket can be balanced in force when the single holes are dug, the deviation can be effectively corrected, and the perpendicularity of the formed groove is ensured; and dig the haplopore earlier, dig the partition wall afterwards, because the length of hole partition wall is less than the grab bucket and opens the fill length, the grab bucket can entangle the partition wall and excavate, can make the grab bucket exert oneself equally, rectifies effectively, guarantees the grooving straightness that hangs down.

The invention is further provided with: after the single hole and the hole partition wall are dug to the designed depth, the grab bucket is sleeved and dug along the length direction of the groove, concave and convex surfaces formed due to different verticality of the grab bucket forming the groove are repaired to be smooth when the grab bucket digs the single hole and the partition wall, and when the grab bucket is sleeved and dug along the length direction of the groove, the grab bucket is lowered to the groove section designed depth to remove the bottom sediment of the groove.

By adopting the technical scheme, the transverse good linearity of the groove section is ensured, and meanwhile, the sediment at the bottom of the groove is also cleaned, so that the cleanness of the interior of the groove is favorably maintained.

The invention is further provided with: during grooving, the corner of the guide wall is correspondingly placed by about 20cm according to the shape of the end face of the grooving machine.

Through adopting above-mentioned technical scheme, when the groover is in underground wall corner to the groover machinery, even hug closely the wall operation of leading, also can be because grab bucket shell and bucket tooth are not in the cause of grooving the section within, and make and leave the surplus soil in the angle, for this reason, put about 20cm according to used grooving machinery end face shape is corresponding outward at the wall corner of leading to the grooving section is not enough, hinders steel reinforcement cage grooving.

The invention is further provided with: and step three, when the steel bars are manufactured, the steel bars are manufactured on a horizontal and flat operation interface.

Through adopting above-mentioned technical scheme, be favorable to maintaining the holistic roughness of steel reinforcement cage of preparation and meet the requirements, general steel reinforcement cage length is longer moreover, and only the roughness of strict control processing platform just can ensure can be smooth when hoist and mount put into the inslot.

The invention is further provided with: and step four, when concrete is poured, simultaneously pouring by using two guide pipes in the same groove section, wherein the distance between the two guide pipes is less than 3m, the distance between the guide pipes and a groove section joint is less than 1.5m, the concrete surfaces corresponding to the two pouring points uniformly rise during pouring, the height difference of the concrete surface at each guide pipe is less than 0.5m, and the pouring is completed before the final setting of the concrete.

Through adopting above-mentioned technical scheme, homogeneity when being favorable to pouring reduces the mutual flow of concrete and the air of parcel, is favorable to the final closely knit degree of concrete.

In conclusion, the invention has the following beneficial effects: the installation and the top process of the joint box are effectively controlled in the construction process of the underground diaphragm wall, the reserved length of the structure is ensured, and a smooth method for pulling out the joint box top is also provided.

Detailed Description

A construction method of an underground diaphragm wall comprises the following steps:

firstly, construction preparation, site cleaning, paying-off measurement, construction of a guide wall and prefabricating of slurry. During measurement and paying-off, according to a base point, a wire point and a level point provided by an owner, a facility worker is arranged in a construction site to measure a control point and the level point, and after a supervision unit checks and accepts the control point and the level point, the center line of the underground diaphragm wall is positioned and lofted. And the base point pile position is frequently retested in the construction process.

When the guide wall is manufactured in the first step, the guide wall is of an integral reinforced concrete structure, the net width is 5cm thicker than that of the underground continuous wall, the top opening of the guide wall is flat with the ground, the guide wall must be inserted into undisturbed soil, and the top surface of the guide wall is higher than the underground water level by more than 1.5m, and the concrete construction method comprises the following steps:

measuring and lofting: and determining the position for excavating the guide wall according to the axis of the underground continuous wall.

Excavating soil: and after measurement and lofting, excavating the guide wall by adopting a method combining mechanical excavation and manual finishing. The elevation of the excavated earth is controlled by manual trimming.

Erecting a mold and pouring concrete: and (4) determining the position of the guide wall on the bottom die, and binding the steel bars. The outer edge of the guide wall is replaced by soil and the inner edge is provided with a vertical steel mould.

Removing the mold and adding a support: the mould can be removed after the concrete reaches certain intensity, simultaneously the upper surface of the inner wall is supported in a layering way, the guide wall is prevented from being extruded inwards, the horizontal distance between the square wood is 2m, and the vertical distance is 1.2 m.

Backfilling: after the guide wall is demolished and supported, the back of the guide wall is immediately backfilled with clay in layers and compacted.

Construction joint: the construction joints of the guide wall should be roughened, and steel bar inserted bars are added to integrate the guide wall, so as to achieve the purpose of no water seepage, and the construction joints should be staggered with the joints of the underground continuous wall.

And (3) guide wall maintenance: after the guide wall is manufactured, when the natural maintenance is carried out to over 70 percent of the design strength, the grooving operation can be carried out, and heavy machinery such as vehicles, cranes and the like is forbidden to be close to the guide wall before.

Wall guiding and framing: after the construction of the guide wall is finished, immediately drawing a framing line on the top surface of the guide wall, and marking the serial number of the unit groove section by red paint; and simultaneously measuring the elevation of the top of each wall, and marking the elevation on a construction drawing for future reference.

Step two, grooving construction; during trenching construction, for construction in a single unit trench section, single holes at two ends of the trench section are dug firstly according to the sequence of firstly digging two sides and then digging the middle, or a method of digging a first hole, then jumping for a distance and then digging a second hole is adopted, so that a partition wall is formed between the two single holes. After the single hole and the hole partition wall are dug to the designed depth, the grab bucket is sleeved and dug along the length direction of the groove, concave and convex surfaces formed due to different verticality of the grab bucket forming the groove are repaired to be smooth when the grab bucket digs the single hole and the partition wall, and when the grab bucket is sleeved and dug along the length direction of the groove, the grab bucket is lowered to the groove section designed depth to remove the bottom sediment of the groove. During grooving, the corner of the guide wall is correspondingly placed by about 20cm according to the shape of the end face of the grooving machine.

Step three, manufacturing and hoisting a reinforcement cage; and thirdly, mounting a joint box when the reinforcement cage is arranged below the reinforcement cage, and backfilling with 3-5m of height in the groove before mounting the joint box. When the steel bar is manufactured, the manufacturing is carried out on a horizontal and flat operation interface. During specific hoisting, the steps and the cautions are as follows:

i, determining a lifting point:

after the reinforcement cage is processed, the reinforcement cage is hoisted in two sections. According to the calculation result of the gravity center of each section of the reinforcement cage, the lifting point is reasonably determined by combining the shape of the reinforcement cage, the reinforcement cage is stably lifted, and the reinforcement cage is vertical by revolving in the air.

II, crane selection:

1 250t crawler crane is used as a main crane and 1 100t crawler crane is used as a secondary crane.

III, hoisting:

the first step is as follows: and screwing the sleeve upwards to separate the upper and lower sections of reinforcement cages.

The second step is that: and (5) transferring the 250t and 100t cranes to a hoisting position, and respectively installing shackles of hoisting points by a crane worker. Firstly, the lower reinforcement cage is hoisted, and three longitudinal hoisting points are arranged. The main crane is 1, and the auxiliary crane is 2.

The third step: and after the installation condition and the stress gravity center of the steel wire ropes of the two cranes are checked, the lower steel reinforcement cage starts to be horizontally hung at the same time. After the reinforcement cage is lifted to be 0.3-0.5 m away from the ground, whether the reinforcement cage is stable or not is checked, the hook is lifted at the last 250t, and the auxiliary machine is commanded to be matched with the hook at any time according to the distance between the tail part of the reinforcement cage and the ground. Until the reinforcement cage is vertically hoisted.

The fourth step: and hoisting the lower reinforcement cage to the notch, aligning and then placing the lower reinforcement cage into the groove, and temporarily placing the upper opening on the guide wall by using a carrying pole.

The fifth step: preparing to lift the upper reinforcement cage, setting 4 longitudinal lifting points, 2 main cranes and 2 auxiliary cranes. The same method is used to hoist to the vertical position. After the reinforcement cage is hoisted, the 250t crane rotates leftwards (or rightwards), and the 100t crane rotates forwards to a proper position, so that the reinforcement cage is vertical to the ground.

And a sixth step: and hoisting the upper reinforcement cage to the notch, and butting the upper reinforcement cage with the lower reinforcement cage. When in butt joint, the steel bars are connected by straight threads, and the I-shaped steel is welded.

The seventh step: after butt joint, the whole reinforcement cage is put into the groove. And (4) placing the steel reinforcement cage on the guide wall by adopting the carrying pole, and dismantling the lifting appliance after determining the elevation without errors.

IV, notes:

① before operation, the construction preparation is carried out, including the inspection of ground level, personnel organization, cranes and other corresponding transportation tools, and the steel wire ropes and the lifting appliances are all arranged according to the maximum weight of the engineering reinforcement cage.

② the construction responsible person must be in place at the hoisting operation site, the hoisting commander and the guardian must make the intersection of the safety and the hoisting parameters, the warning area is divided and set at the site, and the hoisting at night must have enough light illumination.

③ strictly execute the "ten no hang" job protocol.

④ since the reinforcement cage of the underground continuous wall is bulky, in order to ensure that the reinforcement cage is not deformed during the hoisting process, the reinforcement cage hoists the truss, 5 trusses are arranged when the width of the groove is more than 6m, 4 trusses are arranged when the width of the groove is more than or equal to 5m and less than or equal to 6m, the rest are 3 trusses, and the hoisting points are arranged to ensure that the stress of the reinforcement cage is reasonable as much as possible.

⑤ the main crane is not able to reduce the angle of the arm and is not able to turn 360 degrees when loaded.

Step four, pouring and forming concrete; and step four, reserving a naturally cured concrete test block during concrete pouring, and controlling the time and the speed of the joint box jacking according to the solidification time of the concrete test block. When concrete is poured, two guide pipes are simultaneously used for pouring in the same groove section, the distance between the two guide pipes is less than 3m, the distance between the guide pipes and a groove section joint is less than 1.5m, concrete surfaces corresponding to the two pouring points are required to uniformly rise during pouring, the height difference of the concrete surface at each guide pipe is less than 0.5m, and the pouring is completed before the concrete is finally solidified.

And step five, jacking and pulling the joint box, wherein the concrete operation method comprises the following steps of preparing a natural maintenance test block when pouring concrete, formally starting to jack and pull the joint box for 50 ~ 100cm each time, wherein the time for formally starting to jack and pull the joint box is equal to the time for the natural maintenance test block to reach a final set state, and the joint box is lifted every 30min after the first jacking and pulling until the concrete at the uppermost part of the continuous wall is finally set, and the concrete operation method comprises the following specific operation steps:

the specific operation steps are as follows:

(1) after the joint box is hoisted in place, a hydraulic jacking frame is installed;

(2) when pouring concrete, preparing a natural curing test block, formally starting to pull up the joint box, and starting to pull up the joint box for the first time about 4 hours after the concrete is poured according to the time spent on the natural curing test block reaching a final setting state, and then lifting every 30 minutes, wherein the thickness is 50 ~ 100 mm each time, and the joint box is completely pulled out after the final setting;

(3) in the process of jacking and pulling the joint box, the height of the joint box allowed to be jacked is calculated according to a field concrete pouring record table, and early pulling and multi-pulling are strictly forbidden;

(4) the joint box is jacked and pulled by a hydraulic jacking frame, and the crawler crane works in a cooperative manner and is disassembled in sections.