Method for forming waterproof curtain in high-water-level gravel-cobble layer through cast-in-place pile supporting system

Abstract

The invention relates to a method for forming a waterproof curtain in a high-water-level gravel-cobble layer by a cast-in-place pile supporting system, which comprises the following steps of: processing a grouting pipe: selecting a rigid grouting pipe, plugging one end of the grouting pipe, and uniformly forming grouting holes in one side of the grouting pipe along the axis direction of the grouting pipe; a reinforcement cage is machined, specifically, two grouting pipes are used for replacing main reinforcements, so that the connecting line of the grouting pipes is perpendicular to the axis of the reinforcement cage, and grouting holes of the grouting pipes are arranged in a back-to-back mode; the reinforcement cage is placed in the supporting cast-in-place pile, and the connecting line of the two grouting pipes basically coincides with the edge line of the foundation pit during placement; pouring the supporting cast-in-place pile; and sleeve valve pipe segmented grouting is conducted, specifically, grouting is conducted in the two opposite grouting pipes of the two supporting cast-in-place piles at the same time, grout is evenly diffused from grouting holes to the periphery according to the set radius, a waterproof curtain is formed between the piles, and the waterproof curtain is provided with an occlusion area between the piles. The construction method has the effects that the construction difficulty of forming the waterproof curtain on the gravel-cobble layer is reduced, and the construction cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of water-stop curtain construction methods, and in particular to a method for forming a water-stop curtain in a high-water-level gravel layer using a cast-in-place pile support system. Background Art

[0002] In recent years, with the rapid development of my country's national economy and urban construction, deep and large foundation pit support and dewatering projects have gradually increased. The groundwater control system of foundation pit construction mostly adopts the water interception measures of the foundation pit side wall curtain. The curtain often adopts deep mixing pile waterproof curtain, high-pressure swing spray wall, rotary spray pile as water-stop curtain, and underground continuous wall. At present, during the construction of the groundwater control system, it is necessary to use a pile driver to drill holes first, place a steel cage in the hole and pour concrete. After the concrete solidifies to form a supporting cast-in-place pile, use an anchor drill or high-pressure rotary spray pile to drill holes between the two pile bodies to form a grouting hole, and finally pour slurry into the grouting hole. The slurry spreads to both sides and combines with the cast-in-place pile to form a water-stop curtain.

[0003] In foundation pit and slope support projects, water-containing gravel layers are often encountered, which makes it more difficult to drill jet grouting piles. At the same time, support cast-in-place piles and high-pressure jet grouting piles are two different processes, requiring the use of two types of equipment, which requires a larger site and a longer construction period, and is more expensive. When the slurry is combined with the support cast-in-place piles, it has spread to the very end, and there may be insufficient slurry residue. At this time, the support cast-in-place piles have already been formed, resulting in a weaker bonding strength at the junction of the two, which will result in a poor water-stopping effect of the water-stop curtain.

[0004] Therefore, there is an urgent need for a method that has a water-stopping effect that is significantly better than the conventional reinforced concrete cast-in-place pile + high-pressure rotary jet curtain solution, and that reduces the construction difficulty and cost. Summary of the invention

[0005] In order to reduce the construction difficulty of forming a water-stop curtain and reduce the construction cost, and to improve the water-stopping effect of the water-stop curtain, the present application provides a method for forming a water-stop curtain in a high-water-level gravel layer using a cast-in-place pile support system.

[0006] The present application provides a method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system, which adopts the following technical solution: A method for forming a water-stop curtain in a high-water-level gravel layer using a cast-in-place pile support system comprises the following steps: Processing the grouting pipe: selecting a grouting pipe whose rigidity meets the verticality requirement, sealing one end of the grouting pipe, and evenly opening grouting holes on one side of the grouting pipe along its axial direction; Processing the steel cage: using two grouting pipes to replace two main bars, so that the connecting line of the two grouting pipes is perpendicular to the axis of the steel cage, and the grouting holes of the grouting pipes on both sides are arranged opposite to each other; Placing the steel cage: placing the steel cages one by one in the supporting cast-in-place piles, and placing them so that the connecting line of the two grouting pipes coincides with the edge line of the foundation pit; Pouring of supporting cast-in-place piles; The sleeve valve pipe is grouting in sections from bottom to top: the sleeve valve pipe is inserted into the grouting pipe, and grouting is carried out simultaneously into two grouting pipes opposite to the two supporting cast-in-place piles. The slurry spreads evenly from the grouting hole to the surroundings at a set radius, and forms a water-stop curtain between the two supporting cast-in-place piles, and the water-stop curtain has a bite area between the piles.

[0007] By adopting the above technical scheme, two grouting pipes are directly used to replace two main bars, and each steel cage saves the material of two main bars. The grouting pipe and the steel cage are bundled together, which saves the time for the later assembly of the grouting pipe and the steel cage, and the supporting strength of the grouting pipe can also be guaranteed. The grouting pipe and the sleeve valve pipe grouting construction are used in coordination, and the grouting pipe becomes the grouting channel for the sleeve valve pipe grouting construction, and there is no need to drill and bury it separately. Due to the high permeability coefficient of the gravel layer, the slurry is evenly diffused around the multiple grouting holes into the soil and the gravel layer to form a grouting reinforcement body. The reinforcement body forms a closed water-stop curtain between the supporting cast-in-place piles and multiple supporting cast-in-place piles, which reduces the use of high-pressure rotary jet drilling rigs. The installation and grouting costs of the grouting pipe are relatively low, which reduces the equipment cost and construction cost. In addition, the construction of the water-stop curtain is completed when the cast-in-place pile support is completed. There is no need to wait for the supporting cast-in-place piles to meet the requirements before construction, which can effectively shorten the construction period. The grouting pipe is arranged on the pile body of the supporting cast-in-place pile, so that the slurry diffuses from the supporting cast-in-place pile to both sides, and there will be no problem in the prior art that the slurry surplus is insufficient and the supporting cast-in-place pile is closed. The water-stop curtain directly forms a bite area between the two supporting cast-in-place piles, and the water-stop curtain has a higher strength, and has fewer bonding points with the supporting cast-in-place piles, reducing the possibility of water seepage and leakage caused by poor bonding between the slurry and the supporting cast-in-place piles; it can ensure that the formed water-stop curtain is connected to the pile body, reducing the possibility of water leakage and seepage in the later period; and the self-diffusion of the slurry is not limited by the original grouting channel diameter, and the pile diameter is larger; because the grouting pipe is connected with the The steel cages are directly assembled together, so the verticality of the grouting pipe can be guaranteed naturally. The slurry is evenly diffused around the grouting hole, and the verticality of the grouting reinforcement body (i.e., water-stop curtain) formed by the soil and gravel layer can also be guaranteed. The sleeve valve tube grouting process is used in conjunction with the grouting pipe for grouting, and the grouting cost is low. The slurry composition and injection volume can be adjusted to facilitate segmented grouting, which can achieve economic benefits while meeting engineering requirements. At the same time, the grouting is more uniform and denser, making the water-stop curtain formed by solidification stronger.

[0008] Preferably, a grouting sleeve is welded outside the grouting hole, and the grouting sleeve is a cone with a gradually decreasing diameter. When welding, the grouting sleeve is made perpendicular to the grouting pipe, the diameter of the bottom end of the grouting sleeve is 1 / 4~1 / 3 of the diameter of the grouting pipe, and the length of the grouting sleeve is 2~3cm; after the grouting pipe is processed, a plurality of rubber sleeves are sleeved on the grouting pipe to seal the grouting holes one by one, and the thickness of the rubber sleeve is not less than 5mm, and the inner diameter in the relaxed state is not more than 20mm.

[0009] By adopting the above technical solution, the grouting sleeve limits the grouting direction during high-pressure grouting, ensuring that the slurry is evenly diffused in the direction perpendicular to the axis of the grouting pipe, which can effectively ensure the verticality of the water-stop curtain; the grouting sleeve is set to a gradually closing form, which is convenient for increasing the slurry injection speed, thereby increasing the farthest range of the slurry, increasing the bite area of ​​the water-stop curtain, and improving the strength of the water-stop curtain. By setting a rubber sleeve outside each grouting hole, the probability of soil pouring into the grouting hole or even blocking the grouting hole when the steel cage is lowered is avoided; by setting the thickness of the rubber sleeve and the appropriate tension, it is convenient to quickly break the rubber sleeve under the pressure difference of the high-pressure grouting operation, so as to facilitate the rapid grouting operation.

[0010] Preferably, a grouting sleeve is provided on one side of the grouting pipe near each of the grouting holes, each of the grouting sleeves can be inserted into the adjacent grouting holes, one side of each of the grouting sleeves is fixedly connected with a limit plate for being inserted into the inner wall of the grouting pipe, and one side of each of the grouting holes near the outer wall of the grouting hole is provided with a baffle for blocking the grouting hole, and a first locking assembly and a second locking assembly for fixing the relative position of the grouting sleeve and the adjacent grouting pipe side wall are connected between each of the grouting sleeves and the adjacent grouting pipe inner wall, and a push block for driving a plurality of the grouting sleeves to be inserted into the adjacent grouting holes is provided inside the grouting pipe.

[0011] By adopting the above technical scheme, in the process of plugging in the grouting pipe, the grouting hole is blocked by the baffle, thereby reducing the phenomenon of external sludge entering the grouting pipe, and in the process of driving multiple grouting sleeves to be plugged into the grouting hole by the push block, the baffle can also be pushed out of the grouting hole, and through the cooperation of the first locking assembly and the second locking assembly, the position of the grouting sleeve can be restricted, so that the subsequent slurry can flow out from the inside of the grouting sleeve smoothly.

[0012] Preferably, the first locking assembly includes a baffle rod which slides in a horizontal direction and can be inserted into the inside of the limiting plate, the baffle rod is fixedly connected to a tension spring at one end away from the baffle plate, the baffle rod is fixedly connected to a pull block, one side of the pull block is abutted against a baffle, the side of the baffle block close to the pull block is arranged to be an inclined surface which is gradually inclined from a side close to the limiting plate to a side away from the limiting plate to a side close to the pulling block, the end of the baffle block which is away from the pull block and close to the limiting plate is abutted against a push rod which can be inserted into the inside of the limiting plate, and the side of the baffle block abutting against the push rod is arranged to be an inclined surface which is gradually inclined from a side close to the baffle plate to a side away from the baffle plate to a side close to the push rod.

[0013] By adopting the above technical scheme, in the process that the push block drives the grouting sleeve and the limit plate to move toward the grouting hole, the grouting sleeve pushes the baffle plate to push the baffle plate out of the grouting hole, and then the pull block moves away from the baffle plate under the action of the tension spring, and the pull block drives the resistance block to move during the movement, and the resistance block drives the push rod to move during the movement, and the push rod is inserted into the limit plate during the movement, thereby fixing the position of the limit plate.

[0014] Preferably, the second locking assembly includes a sliding rod fixedly connected to the limit plate, the sliding rod slidingly passes through the grouting pipe arrangement, a plurality of hinged rods are hinged on the side wall of the sliding rod, the end of each hinged rod is hinged with a rotating rod, and the end of each rotating rod away from the hinged rod is rotatably and slidably connected to the adjacent side wall of the sliding rod, and a fixed block for abutting against one end of the plurality of rotating rods away from the hinged rod is fixedly connected to the side wall of the grouting pipe, and a stopper is abutted on the side of the rotating rod away from the baffle, and the stopper is connected with one end plugged into The limiting rod inside the baffle plate, one side of the hinged rod abuts with a push rod, one side of the push rod abuts with an extrusion block, and the push rod can drive the extrusion block to move under the drive of the hinged rod, one side of the extrusion block abuts with a locking rod, and the locking rod can be inserted into the limiting plate under the drive of the extrusion block, and the middle position of the connected hinged rod and the rotating rod and the side away from the sliding rod are provided with a locking block for limiting the movement of the hinged rod and the rotating rod in the direction close to the sliding rod, and one side of each locking block is fixedly connected with a locking spring.

[0015] By adopting the above technical solution, in the process of the push block driving the limit plate and the grouting sleeve to move toward the side close to the grouting pipe, the limit plate drives the sliding rod to move, and the sliding rod abuts against the fixed block through the end during the movement, thereby driving the connection between the multiple hinged rods and the connected rotating rod to move toward the side away from the sliding rod, and then the locking block limits the position of the hinged rod and the rotating rod driven by the locking spring. In the process of the movement of the hinged rod and the rotating rod, the rotating rod drives the block and the limit rod to move, so that the limit block moves from the inside of the baffle, and then the baffle can be moved out of the grouting hole driven by the grouting sleeve. The hinged rod drives the push rod to move, and the push rod drives the squeeze block to move during the movement, and the squeeze block drives the locking rod to be inserted into the inside of the limit plate, thereby realizing the limitation of the position of the limit plate.

[0016] Preferably, sleeve valve pipe high-pressure grouting construction is carried out within 4 to 10 hours after the pouring of the supporting cast-in-place piles is completed.

[0017] By adopting the above technical solution and using sleeve valve pipe grouting construction, the time for grouting construction can be shortened to 4 to 10 hours after the pouring of the supporting bored piles is completed, effectively shortening the construction period.

[0018] Preferably, during grouting, the grouting construction parameters are set according to the ground conditions and the spacing between the supporting cast-in-place piles, and the grouting construction is divided into three stages from bottom to top: Set the first section grouting height to 1 / 4 of the grouting pipe height, set the second section grouting height to 1 / 2, set the third section grouting height to 1 / 4 of the grouting pipe height, and set the grouting pressure and grouting volume according to the distribution of pebbles in the formation.

[0019] By adopting the above technical solution, the formed water curtain is made more uniform and dense, and the strength of the water-stopping curtain is higher.

[0020] Preferably, after grouting is completed, a hard water pipe is quickly inserted into the bottom of the grouting pipe until the bottom of the grouting pipe, and clean water is pressed into the grouting pipe for cleaning. The water injection rate is not less than 90L per minute, and water is continuously injected for more than 2 minutes until the water returns to the orifice of the grouting pipe clearly.

[0021] By adopting the above technical solution, normal pressure water is introduced into the grouting pipe to clean the slurry residue in the grouting pipe, ensuring that there is no sediment in the grouting pipe and the grouting channel is unobstructed, which is convenient for subsequent grouting and reuse of the grouting pipe.

[0022] Preferably, when the supporting cast-in-place piles and grouting reinforcement bodies meet the requirements, the foundation pit excavation begins. During the foundation pit excavation, the grouting reinforcement of the soil between the piles is inspected. If local leakage is found or the soil between the piles is not dense enough, precise directional grouting is performed again through the grouting pipe.

[0023] By adopting the above technical scheme, since the verticality deviation of the bored pile in the gravel layer is large, it is impossible to judge the deviation direction of the supporting bored pile during the construction of the high-pressure rotary jet pile, and it is impossible to ensure the interlocking connection with the supporting bored pile. The unconnected part often becomes a leakage area. The present application adopts a grouting pipe for grouting, which can be supplemented with grouting twice, three times or more times in the later stage, leaving a grouting channel for the treatment of accidental water leakage in the foundation pit, and avoiding the problem of water leakage plugging of the conventional high-pressure rotary jet pile water-stopping curtain; it can provide an effective groundwater blocking solution throughout the life cycle before, during and after the excavation of the foundation pit, providing a feasible solution for the safe use and maintenance of the foundation pit in the later stage.

[0024] Preferably, the grouting pipe uses a seamless steel pipe with an outer diameter of 50 mm and a wall thickness of 5 mm.

[0025] By adopting the above technical solution, the support stiffness of the seamless steel pipe meets the requirements, and it is easy to process and has a low cost. It is easy to process it together with other parts on the construction site, or use local materials, which is conducive to further saving construction costs.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: The grouting pipe is used to replace the main reinforcement of the two steel cages, and the grouting pipe and the steel cage are assembled together in advance. The grouting pipe not only bears the supporting performance of the main reinforcement, but also serves as the grouting sleeve of the sleeve valve pipe, and can be combined with the sleeve valve pipe grouting process for grouting; compared with the traditional method of forming a water-stop curtain between high-pressure rotary jet piles, no drilling machinery and equipment are required for drilling construction, and no high-pressure rotary jet drilling rig is required for rotary jetting piles. The on-site mechanical equipment is directly halved, which is convenient for engineering process arrangement and on-site management; the drilling rig hole-making cost and the rotary jet drilling rig pile-making cost are saved, and the grouting The cost of slurry pipe installation and grouting is relatively low, and it is estimated that the cost can be saved by about 25%; this construction plan can be completed as the supporting cast-in-place piles are completed, and there is no need to calculate the construction period separately. It can save about 5 days of construction time compared with the conventional high-pressure rotary jet pile process; the form of slurry self-diffusion is not limited by the original grouting hole diameter, and the pile diameter is larger; the slurry diffuses from the supporting cast-in-place piles to both sides, combines in the middle to form a bite area, the combination points are reduced, and the strength of the combination points between the water-stop curtain and the supporting cast-in-place piles and the overall strength of the water-stop curtain are higher.

[0027] By carrying out grouting construction three times from bottom to top, it is ensured that the formed water-stop curtain is more uniform and denser, thereby improving the water-stop effect of the water-stop curtain.

[0028] Grouting is carried out using grouting pipes, which can be supplemented with grouting twice, three times or more times in the later stage. A grouting channel is reserved for the treatment of accidental water leakage in the foundation pit, which can avoid the problem of plugging water leakage with conventional high-pressure rotary jet pile water-stop curtains. An effective groundwater blocking solution can be provided throughout the entire life cycle before, during and after foundation pit excavation, which provides a feasible solution for the safe use and maintenance of the foundation pit in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the construction flow chart of this application.

[0030] Figure 2 It is a schematic diagram of the structure of the grouting pipe of Example 1 of the present application.

[0031] Figure 3 It is a schematic diagram of the structure of the grouting pipe after the grouting sleeve is processed in Example 1 of the present application.

[0032] Figure 4 This is a schematic diagram of the steel cage after it is placed in the supporting cast-in-place piles.

[0033] Figure 5 It is a schematic diagram of the water-stop curtain formed between piles after the sleeve valve pipe grouting is completed.

[0034] Figure 6 It is a structural schematic diagram of a sleeve valve tube.

[0035] Figure 7 This is a cross-sectional view of the grouting pipe of Example 2 of the present application.

[0036] Figure 8 yes Figure 7 A partial enlarged schematic diagram of the structure A in the middle.

[0037] Fig. 9 It is a schematic diagram of the structure of the second locking assembly of Example 2 of the present application.

[0038] Explanation of the reference numerals in the accompanying drawings: 1. grouting pipe; 11. grouting hole; 12. baffle; 2. grouting sleeve; 21. limit plate; 3. steel cage; 31. main reinforcement; 4. supporting bored pile; 5. sleeve valve pipe; 6. water-stop curtain; 61. bite area; 7. push block; 8. first locking assembly; 81. stop rod; 82. pull block; 83. tension spring; 84. stop block; 85. compression spring; 86. push rod; 9. second locking assembly; 91. slide rod; 911. hinged rod; 912. rotating rod; 913. fixed block; 92. locking block; 921. locking spring; 93. stop block; 94. limit rod; 95. push rod; 96. squeezing block; 97. locking rod. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1-9 This application is described in further detail.

[0040] The embodiment of the present application discloses a method for forming a water-stop curtain in a high-water-level gravel layer using a cast-in-place pile support system. Example

[0041] Reference Figure 1 The method for forming a water-stop curtain in a high-water gravel layer by a cast-in-place pile support system comprises the following steps: S1: Processing grouting pipe 1.

[0042] A grouting pipe 1 whose rigidity meets the verticality requirement is selected, one end of the grouting pipe 1 is blocked, and grouting holes 11 are evenly opened on one side of the grouting pipe 1 along its axial direction. This application is described by taking the grouting pipe 1 as an example in which a seamless steel pipe with an outer diameter of 50 mm and a wall thickness of 5 mm is used, and a row of grouting holes 11 is opened on the seamless steel pipe, and the spacing between adjacent grouting holes 11 is 10-15 cm.

[0043] After the grouting hole 11 is processed, the grouting sleeve 2 is welded outside the grouting hole 11, and the grouting sleeve 2 is made perpendicular to the grouting pipe 1 during welding. To ensure that the slurry is vertically ejected from the grouting hole 11 and the grouting sleeve 2, and evenly diffused to the surroundings, the verticality of the water-stop curtain 6 can be effectively guaranteed. In addition, the grouting sleeve 2 is a cone with a gradually decreasing diameter. The diameter of the bottom end of the grouting sleeve 2 is 1 / 4 to 1 / 3 of the diameter of the grouting pipe 1, and the length of the grouting sleeve 2 is 2 to 3 cm. The grouting sleeve 2 is set to a gradually closing form, which is convenient for increasing the injection speed of the slurry, thereby increasing the farthest range of the slurry, increasing the area of ​​the bite area 61 forming the water-stop curtain 6, and improving the strength of the water-stop curtain 6.

[0044] After the grouting pipe 1 is processed, a plurality of rubber sleeves are set on the grouting pipe 1 to block the grouting holes 11 one by one, and the thickness of the rubber sleeves is not less than 5mm, and the inner diameter in the relaxed state is not more than 20mm. When the steel cage 3 is lowered, the soil is prevented from pouring into the grouting holes 11, and even blocking the grouting holes 11; by setting the thickness of the rubber sleeve and the appropriate tension, the rubber sleeve can be quickly broken under the pressure difference of the high-pressure grouting operation, so as to facilitate the rapid grouting operation.

[0045] S2: Processing steel cage 3.

[0046] Two grouting pipes 1 are used to replace the two main bars 31 , so that the connecting line of the two grouting pipes 1 is perpendicular to the axis of the steel cage 3 , and the grouting holes 11 of the grouting pipes 1 on both sides are arranged back to back.

[0047] Each steel cage 3 saves the material of two main bars 31, and the grouting pipe 1 and the steel cage 3 are bundled together, which saves the time of assembling the grouting pipe 1 with the steel cage 3 in the later stage, and the supporting strength of the grouting pipe 1 can also be guaranteed. Since the grouting pipe 1 is assembled with the direct steel cage 3, after the pouring construction of the supporting cast-in-place pile 4 is completed, the grouting pipe 1 is set on the pile body of the supporting cast-in-place pile 4, which can ensure that the formed water-stop curtain 6 is connected to the pile body, reducing the possibility of water leakage and water seepage in the later stage, and the verticality of the water-stop curtain 6 can also be guaranteed.

[0048] S3: Place the steel cage 3.

[0049] The steel cages 3 are placed one by one in the supporting cast-in-place piles 4, and the connection line of the two grouting pipes 1 is basically coincident with the edge line of the foundation pit.

[0050] S5: Cast-in-place support pile 4 pouring construction.

[0051] S6: The sleeve valve pipe 5 is grouted in sections from bottom to top. The section grouting construction is carried out within 4 to 10 hours after the support pile 4 is grouted. The sleeve valve pipe 5 is used for grouting construction, and the time for grouting construction can be shortened to 4 to 10 hours after the support pile 4 is grouted, which effectively shortens the construction period.

[0052] The sleeve valve tube 5 is inserted into the grouting pipe 1, and grouting is carried out simultaneously into the two grouting pipes 1 opposite to the two supporting cast-in-place piles 4. Since the permeability coefficient of the gravel layer is relatively high, the slurry is evenly diffused into the soil and the gravel layer around the multiple grouting holes 11 to form a grouting reinforcement body. The grouting reinforcement body forms a closed water-stop curtain 6 between the supporting cast-in-place piles 4 and the multiple supporting cast-in-place piles 4. There is no need to use a high-pressure rotary jet drilling rig to form piles in advance, and the installation and grouting costs of the grouting pipe 1 are relatively low, which reduces the equipment cost and the construction cost; and the construction of the water-stop curtain 6 is completed when the cast-in-place pile support is completed, and there is no need to wait for the supporting cast-in-place piles 4 to meet the requirements before construction, which can effectively shorten the construction period.

[0053] During grouting, the grouting construction parameters are set according to the formation conditions and the spacing between the supporting cast-in-place piles 4, and the grouting construction is divided into three stages. The slurry is evenly diffused from the grouting hole 11 to the surroundings at a set radius, and a water-stop curtain 6 is formed between two supporting cast-in-place piles 4, and the water-stop curtain 6 has a bite area 61 between the piles.

[0054] The sleeve valve tube 5 grouting process cooperates with the grouting pipe 1 for grouting, and the grouting cost is low. By adjusting the slurry composition and the injection amount of the slurry, it is easy to achieve segmented grouting, which can achieve economic benefits while meeting the engineering requirements. At the same time, the grouting is more uniform and denser, so that the water-stop curtain 6 formed by solidification has higher strength.

[0055] Specifically, the first grouting height is set to 1 / 4 of the height of the grouting pipe 1, the second grouting height is set to 1 / 2, and the third grouting height is set to 1 / 4 of the height of the grouting pipe 1. The grouting pressure and grouting amount are set according to the distribution of pebbles in the formation.

[0056] After grouting is completed, quickly insert a hard water pipe into the bottom of the grouting pipe 1 until it reaches the bottom of the grouting pipe 1, press clean water into the grouting pipe 1 for cleaning, and the water injection volume should be no less than 90L per minute. Continuously inject water for more than 2 minutes until the water on the orifice of the grouting pipe 1 is completely clear, ensuring that there is no sediment in the grouting pipe 1 and the grouting channel is unobstructed, which is convenient for later grouting and reuse of the grouting pipe 1.

[0057] When the supporting cast-in-place piles 4 and the grouting reinforcement bodies meet the requirements, the foundation pit is excavated. During the excavation of the foundation pit, the grouting reinforcement of the soil between the piles is inspected. If local leakage is found or the soil between the piles is not dense enough, the grouting pipe 1 is precisely oriented again. Grouting with the grouting pipe 1 can be supplemented twice, three times or more times in the later stage, leaving a grouting channel for the treatment of accidental water leakage in the foundation pit, and avoiding the problem of water leakage plugging of the conventional high-pressure rotary jet pile water-stopping curtain 6; it can provide an effective groundwater blocking solution for the entire life cycle before, during and after the foundation pit excavation, providing a feasible solution for the safe use and maintenance of the foundation pit in the later stage. Example

[0058] Reference Figure 7-9 The difference between the present embodiment 2 and the embodiment 1 is that the grouting sleeve 2 is located inside the grouting pipe 1 and is arranged one by one with the grouting holes 11. The end of each grouting sleeve 2 is arranged toward the corresponding grouting pipe 1.

[0059] Each grouting sleeve 2 is fixedly connected to a limit plate 21 on one side away from the inner wall of the grouting pipe 1, and each limit plate 21 is provided with a through hole connected to the inner opening of the grouting sleeve 2. The grouting pipe 1 is provided with a first locking assembly 8 and a second locking assembly 9 for limiting the position of the baffle 12 and the grouting sleeve 2.

[0060] A push block 7 is provided inside the grouting pipe 1. The push block 7 is set to be conical, and the cone vertex is set downward. The push block 7 can abut against multiple limit plates 21 during movement, and drive the limit plates 21 to move toward the direction close to the side wall of the grouting pipe 1.

[0061] In actual use, during the process of plugging the grouting pipe 1, the baffle 12 blocks the grouting hole 11 opened on the side wall of the grouting pipe 1. Then, when grouting is required, the push block 7 inside the grouting pipe 1 is driven to move through the sleeve valve pipe 5. Then, the push block 7 drives the multiple limit plates 21 inside the grouting pipe 1 to move close to the relatively arranged grouting hole 11 during the movement. Then, the grouting sleeve 2 is plugged into the grouting hole 11. After the grouting sleeve 2 is plugged into the grouting hole 11, the baffle 12 is pushed out from the grouting hole 11. Then, the first locking assembly 8 and the second locking assembly 9 jointly limit the position of the limit plate 21, thereby realizing the process of guiding the slurry to move to the outside of the grouting pipe 1.

[0062] The first locking assembly 8 includes a stopper 81, the length direction of which is parallel to the length direction of the grouting pipe 1, and the stopper 81 is slidably inserted into the side wall of the grouting pipe 1 in a direction parallel to the axis of the grouting pipe 1. One end of the stopper 81 close to the baffle 12 is slidably inserted into the inside of the side wall of the limiting plate 21 and can be moved out of the limiting plate 21 to the side close to the axis of the grouting pipe 1.

[0063] A pull block 82 is fixedly connected to the side of the stopper 81 away from the limit plate 21, and a tension spring 83 is fixedly connected between the side of the pull block 82 away from the stopper 81 and the inner wall of the opposite grouting pipe 1. A stopper 84 is abutted on the side of the pull block 82 close to the limit plate 21, and the side of the stopper 84 abutting against the pull block 82 is set as an inclined surface, and the inclined surface is gradually inclined from the side close to the adjacent grouting hole 11 to the side away from the adjacent grouting hole 11 to the side close to the connected pull block 82. A compression spring 85 is abutted on the side of the stopper 84 away from the adjacent grouting hole 11, and the side of the compression spring 85 away from the stopper 84 is fixedly connected to the inner wall of the opposite grouting pipe 1.

[0064] The side of the stopper 84 away from the pull block 82 and close to the grouting hole 11 is abutted with a push rod 86, and the side of the stopper 84 abutting against the push rod 86 is set to gradually tilt from the side close to the adjacent grouting hole 11 to the side away from the grouting hole 11 to the side close to the push rod. The push rod 86 is slidably inserted into the side wall of the grouting pipe 1 in a direction perpendicular to the axis of the grouting pipe 1, and the end of the push rod 86 away from the stopper 84 can be inserted into the adjacent limit plate 21.

[0065] During the movement of the grouting sleeve 2 into the grouting hole 11, the grouting sleeve 2 abuts against the baffle 12 and moves the baffle 12 out of the grouting hole 11, and then the baffle rod 81 and the pull block 82 move in a direction away from the adjacent grouting hole 11 under the action of the tension spring 83. During the movement, the pull block 82 drives the abutment block 84 to move toward the side close to the push rod. During the movement, the abutment block 84 cooperates with the compression spring 85 to drive the push rod 86 to move toward the position limit plate 21 inserted into the adjacent grouting hole 11, so as to be inserted into the position limit plate 21, thereby fixing the position of the position limit plate 21.

[0066] The second locking assembly 9 includes a slide bar 91 fixedly connected to one side of the grouting sleeve 2, and the slide bar 91 is arranged in a direction perpendicular to the axis of the grouting pipe 1. Two opposite side walls of the slide bar 91 are hinged with hinged rods 911, and the length direction of each hinged rod 911 is arranged parallel to the length direction of the connected slide bar 91. A rotating rod 912 is hinged on one side of each hinged rod 911 away from the connected limit plate 21, and the end of each rotating rod 912 is rotatably and slidably connected to the adjacent side wall of the slide bar 91.

[0067] The grouting pipe 1 is provided with a through hole for the sliding rod 91 to penetrate the grouting pipe 1 in a direction perpendicular to the grouting pipe 1 , and the inner wall of the through hole is fixedly connected to two relatively arranged fixed blocks 913 near the outer wall of the grouting pipe 1 , and the two fixed blocks 913 are arranged one-to-one with the two rotating rods 912 .

[0068] Two oppositely arranged locking blocks 92 are arranged on opposite sides of the through hole in the grouting pipe 1, and the sides of the two locking blocks 92 close to the adjacent hinged rods 911 and the rotating rods 912 are arranged as inclined surfaces gradually inclined from the direction of approaching each other to the direction of moving away from each other in the direction of the adjacent hinged rods 911 and the rotating rods 912. The opposite sides of the two adjacent locking blocks 92 are fixedly connected with locking springs 921, and the locking springs 921 are used to drive the connected locking blocks 92 to move in the direction close to the other adjacent locking blocks 92.

[0069] After the grouting sleeve 2 is inserted into the grouting hole 11, the rotating rod 912 drives the hinged rod 911 to rotate under the drive of the fixed block 913, so that the hinged rod 911, the rotating rod 912 and the sliding rod 91 can form a triangle. And every two adjacent locking blocks 92 can be inserted into the hinge of the adjacent rotating rod 912 and the hinged rod 911, close to the side of the sliding rod 91 and abut against the adjacent rotating rod 912 and the hinged rod 911, so as to fix the position of the limit plate 21 and the grouting sleeve 2.

[0070] A stopper 93 is inserted and slidably connected to one side of the through hole opened on the side wall of the grouting pipe 1 and close to the outer wall of the grouting pipe 1 along the axial direction of the grouting pipe 1. The stopper 93 is used to abut against the rotating rod 912 inserted into the through hole on the side wall of the grouting pipe 1. A limit rod 94 is fixedly connected to the side of the stopper 93 close to the grouting hole 11. The length direction of the limit rod 94 is parallel to the axial direction of the grouting pipe 1 and is inserted and slidably connected to the inside of the grouting pipe 1 along its own length direction. The end of the limit rod 94 away from the stopper 93 is inserted into the inside of the baffle 12.

[0071] After the grouting sleeve 2 is inserted into the grouting hole 11, the rotating rod 912 rotates after abutting against the fixed block 913 and drives the stop block 93 to move toward the side away from the sliding rod 91. During the movement, the stop block 93 drives the limiting rod 94 to move. During the movement, the limiting rod 94 moves toward the side away from the limiting plate 21, thereby moving out of the limiting plate 21, so that the limiting plate 21 can be moved out of the grouting hole 11 driven by the grouting sleeve 2.

[0072] A push rod 95 is provided inside the grouting pipe 1 at a side of the through hole away from the grouting hole 11 and at a side of the two oppositely arranged locking blocks 92 away from the stopper 93. The push rod 95 is slidably inserted into the grouting pipe 1 in a direction perpendicular to the axis of the grouting pipe 1 and can abut against the adjacent hinged rod 911. A squeeze block 96 abuts against the side of the push rod 95 away from the hinged rod 911. The side of the squeeze block 96 abutting against the push rod 95 is set as an inclined surface that gradually tilts from the side close to the hinged rod 911 to the side away from the hinged rod 911 to the side close to the push rod 95.

[0073] The side of the squeeze block 96 away from the push rod 95 is abutted with a locking rod 97, and the side of the squeeze block 96 abutting against the locking rod 97 is set as an inclined surface that gradually tilts from the side close to the hinge rod 911 to the side away from the hinge rod 911 to the side close to the locking rod 97. The locking rod 97 is slidably inserted into the grouting pipe 1 along a direction parallel to the length direction of the grouting pipe 1, and the end of the locking rod 97 away from the squeeze block 96 can be inserted into the inside of the limit rod 94.

[0074] After the grouting sleeve 2 is inserted into the grouting hole 11, when the rotating rod 912 drives the hinged rod 911 to rotate under the action of the stopper 93, the hinged rod 911 drives the push rod 95 to move to the side away from the slide rod 91. The push rod 95 drives the squeeze block 96 to move during the movement, and the squeeze block 96 drives the locking rod 97 to move during the movement. The locking rod 97 is inserted into the inside of the limit plate 21, thereby realizing the fixing process of the limit plate 21.

[0075] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system, characterized in that: The steps include: Processing the grouting pipe (1): selecting a grouting pipe (1) whose rigidity meets the verticality requirement, sealing one end of the grouting pipe (1), and evenly opening grouting holes (11) on one side of the grouting pipe (1) along the axial direction thereof; Processing the steel cage (3): using two grouting pipes (1) to replace two main bars (31), so that the two grouting pipes (1) and the axis of the steel cage form an angle α, the angle α is 0° to 30°, and the grouting holes (11) of the grouting pipes (1) on both sides are arranged opposite to each other; Placing the steel cages (3): placing the steel cages (3) one by one in the supporting cast-in-place piles (4), and placing the two grouting pipes (1) symmetrically or asymmetrically. When the two grouting pipes are asymmetrically placed, the angle between the grouting pipes and the edge line of the foundation pit does not exceed 30°; Pouring supporting cast-in-place piles (4); The sleeve valve tube (5) is grouted in sections from bottom to top: the sleeve valve tube (5) is inserted into the grouting tube (1), and grouting is simultaneously performed into two grouting tubes (1) opposite to the two supporting cast-in-place piles (4), the grouting liquid is uniformly diffused from the grouting hole (11) to the surroundings at a set radius, and a water-stop curtain (6) is formed between the two supporting cast-in-place piles (4), and the water-stop curtain (6) has a bite area (61) between the piles.

2. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to claim 1, characterized in that: A grouting sleeve (2) is welded outside the grouting hole (11), and the grouting sleeve (2) is a cone with a gradually decreasing diameter. When welding, the grouting sleeve (2) is perpendicular to the grouting pipe (1). The diameter of the bottom end of the grouting sleeve (2) is 1 / 4 to 1 / 3 of the diameter of the grouting pipe (1), and the length of the grouting sleeve (2) is 2 to 3 cm; After the grouting pipe (1) is processed, a plurality of rubber sleeves are sleeved on the grouting pipe (1) to seal the grouting holes (11) one by one, and the thickness of the rubber sleeves is not less than 5 mm, and the inner diameter in the relaxed state is not greater than 4 times the outer diameter of the grouting pipe (1).

3. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to claim 1, characterized in that: A grouting sleeve (2) is provided on one side of the grouting pipe (1) near each grouting hole (11), and each grouting sleeve (2) can be inserted into an adjacent grouting hole (11). A stopper plate (21) for inserting into the inner wall of the grouting pipe (1) is fixedly connected to one side of each grouting sleeve (2). A baffle plate (12) for blocking the grouting hole (11) is provided on one side of each grouting hole (11) near the outer wall of the grouting hole (11). A first locking assembly (8) and a second locking assembly (9) for fixing the relative position of the grouting sleeve (2) and the side wall of the adjacent grouting pipe (1) are connected between each grouting sleeve (2) and the inner wall of the adjacent grouting pipe (1). A push block (7) for driving a plurality of grouting sleeves (2) to be inserted into the adjacent grouting holes (11) is provided inside the grouting pipe (1).

4. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to claim 3, characterized in that: The first locking assembly (8) comprises a blocking rod (81) which slides in a horizontal direction and can be inserted into the interior of the limiting plate (21); one end of the blocking rod (81) which is away from the limiting plate (12) is fixedly connected to a tension spring (83); the blocking rod (81) is fixedly connected to a pulling block (82); one side of the pulling block (82) is abutted against a blocking block (84); a side of the blocking block (84) close to the pulling block (82) is arranged to be moved from a side close to the limiting plate (21) to a side away from the limiting plate (21). The side of the stop block (84) is provided with an inclined surface which gradually inclines toward a side close to the pull block (82); one end of the stop block (84) which is away from the pull block (82) and close to the limit plate (21) is abutted with a push rod (86) which can be inserted into the inside of the limit plate (21); and the side of the stop block (84) abutting against the push rod (86) is provided with an inclined surface which gradually inclines from a side close to the baffle plate (12) to a side away from the baffle plate (12) to a side close to the push rod (86).

5. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to claim 3, characterized in that: The second locking assembly (9) comprises a sliding rod (91) fixedly connected to the limit plate (21), the sliding rod (91) slidingly passes through the grouting pipe (1), a plurality of hinged rods (911) are hinged on the side wall of the sliding rod (91), and a rotating rod (912) is hinged at the end of each hinged rod (911), and an end of each rotating rod (912) away from the hinged rod (911) is rotatably and slidably connected to the adjacent side wall of the sliding rod (91), and a fixed block (913) is fixedly connected to the side wall of the grouting pipe (1) for abutting against one end of the plurality of rotating rods (912) away from the hinged rod (911), and a stopper (93) is abutted on the side of the rotating rod (912) away from the baffle (12), and one end of the stopper (93) is connected to and inserted into the baffle (12). An internal limiting rod (94), one side of the hinged rod (911) is abutted with a push rod (95), one side of the push rod (95) is abutted with an extrusion block (96), and the push rod (95) can drive the extrusion block (96) to move under the drive of the hinged rod (911), one side of the extrusion block (96) is abutted with a locking rod (97), and the locking rod (97) can be inserted into the inside of the limiting plate (21) under the drive of the extrusion block (96), and the middle position of the connected hinged rod (911) and the rotating rod (912) and the side away from the sliding rod (91) are provided with a locking block (92) for limiting the movement of the hinged rod (911) and the rotating rod (912) in the direction close to the sliding rod (91), and one side of each locking block (92) is fixedly connected with a locking spring (921).

6. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to any one of claims 1 to 5, characterized in that: The segmented grouting construction is carried out within 4 to 10 hours after the support cast-in-place piles (4) are cast.

7. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to any one of claims 1 to 5, characterized in that: During grouting, the grouting construction parameters are set according to the ground conditions and the spacing between the supporting cast-in-place piles (4), and the grouting construction is divided into three stages from bottom to top: The first grouting height is set to 1 / 4 of the height of the grouting pipe (1), the second grouting height is set to 1 / 2, and the third grouting height is set to 1 / 4 of the height of the grouting pipe (1). The grouting pressure and grouting volume are set according to the distribution of pebbles in the stratum.

8. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to any one of claims 1 to 5, characterized in that: After grouting is completed, a hard water pipe is quickly inserted into the bottom of the grouting pipe (1) until it reaches the bottom of the grouting pipe (1), and clean water is pressed into the grouting pipe (1) for cleaning. The water injection rate is not less than 90L per minute, and water injection is continued for more than 2 minutes until the water on the orifice of the grouting pipe (1) is clear.

9. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to any one of claims 1 to 5, characterized in that: When the supporting cast-in-place piles (4) and the grouting reinforcement bodies meet the requirements, the foundation pit is excavated. During the foundation pit excavation, the grouting reinforcement of the soil between the piles is inspected. If local leakage is found or the soil between the piles is not dense enough, directional grouting is injected into the grouting pipe (1) again.

10. The method for forming a water-stop curtain in a high-water gravel layer using a cast-in-place pile support system according to any one of claims 1 to 5, characterized in that: The grouting pipe (1) uses a seamless steel pipe with an outer diameter of 50 mm and a wall thickness of 5 mm.

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