Construction method of deep foundation pit near river

Abstract

The invention relates to the technical field of foundation pit supporting, in particular to a river-facing deep foundation pit construction method which comprises the following steps: S1, radar detection outside a foundation pit; s2, the stand column piles and the steel pipe piles are installed; s3, the outer side of the supporting wall is subjected to grouting reinforcement treatment; s4, excavation of a foundation pit; s5, construction of a first concrete support; s6, an inner supporting lifting frame is manufactured; s7, construction of a second concrete support; s8, mounting a support in the steel pipe; and S9, blocking the support wall. According to the construction method, through an engaged pile body structure of the supporting wall, accurate grouting reinforcement based on radar detection on the outer side of the supporting wall, curtain formation, layered excavation of a foundation pit, multi-channel inner supporting of the supporting wall, inner supporting lifting frame and sectional type formwork pouring, the purposes of improving the anti-seepage performance, safety and reliability in the construction process are achieved; the overall stability of the supporting system is improved, and the effect of saving materials is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of foundation pit support, and particularly relates to a deep foundation pit construction method adjacent to a river. BACKGROUND

[0002] The deep foundation pit construction method adjacent to a river is mainly used for deepening operation on an existing or newly-built foundation pit in a region adjacent to a river, lake, sea or the like, and having complex geological conditions and a high underground water level, so as to ensure safety and stability during deepening of the foundation pit, minimize disturbance to surrounding buildings, embankments and underground water environment, and achieve the purpose of safely, efficiently and environmentally protecting expanding underground space in a sensitive region adjacent to a river.

[0003] At present, there are strata with strong water permeability such as sand layer and silt layer in the region adjacent to a river, and after excavation of the foundation pit, the water head difference between the river and the water inside the foundation pit is significantly increased (especially during flood period and high tide), and water flow can carry fine particles in the soil through pores or gaps of the supporting structure to flow away, forming piping; if a large amount of fine particles are carried away, it can also cause quicksand, resulting in local instability or collapse of the pit bottom or slope, so that the supporting structure needs to bear a combined load of greater earth pressure + water pressure; and the water pressure on the side adjacent to the river changes dynamically with the water level, which can cause "alternating stress" of the supporting structure, causing excessive deformation, which can easily cause cracking and overturning of the supporting structure. SUMMARY

[0004] The purpose of the present application is to provide a deep foundation pit construction method adjacent to a river, which improves the anti-seepage performance, safety and reliability during construction, improves the stability of the overall supporting system and saves materials.

[0005] Based on this, the present application provides a deep foundation pit construction method adjacent to a river, comprising: S1, radar detection outside the foundation pit: using a radar vehicle to perform omnidirectional scanning and detection on the peripheral soil body of the supporting wall on both sides of the foundation pit, and accurately judging whether there are cavities, loose interlayers and other adverse geological structures inside the soil body through reflection signals of electromagnetic waves emitted by the radar at different medium interfaces, so as to avoid collapse caused by soil disturbance during excavation of the foundation pit; S2, installation of column piles and steel pipe piles: after completing radar detection and determining the soil condition, a drilling machine is used to drill column pile installation holes for installing column piles and steel pipe pile installation holes for installing steel pipe piles on both sides of the column pile installation holes at preset positions, then a rock bolt machine is used to vertically place a reinforcement cage + lattice column into the column pile installation hole and a steel pipe column into the steel pipe pile installation hole, and finally concrete is injected into the column pile installation hole and the steel pipe column respectively, so as to form column piles and a plurality of steel pipe piles after the concrete solidifies; S3, grouting reinforcement treatment outside the supporting wall: after the construction of the column and the steel pipe pile is completed and meets the safety requirements, a sleeve valve pipe installation hole is drilled in the soil using a drilling machine according to the size of the sleeve valve pipe, each cavity in the direction of the preset depth is connected through the sleeve valve pipe installation hole, the sleeve valve pipe is installed in the sleeve valve pipe installation hole, and each cavity in the soil outside the supporting wall is injected with concrete through the sleeve valve pipe to reinforce the soil and form a complete anti-seepage reinforcement curtain. S4, foundation pit excavation: after the soil outside the supporting wall is grouted and reinforced, the soil and rock are excavated using a mechanical excavation method, and the excavation sequence is determined according to the principles of "stratification, segmentation, symmetry, balance, and timeliness" to ensure the normal excavation of the foundation pit. S5, construction of the first concrete support: the pouring formwork is erected on both sides of the column, and the two ends of the pouring formwork are connected to the two supporting walls to form a first concrete inner support installation cavity, and the first concrete inner support installation cavity is injected with concrete, and the first concrete support is formed after the concrete is solidified. S6, production of the inner support lifting frame: when the foundation pit is excavated to the first preset depth, the inner support lifting frame is installed on the plurality of steel pipe columns, the steel disc is connected to the pre-marked position outside the steel pipe column, the first triangular iron is connected to the steel disc near the ground on one side, and the other side of the first triangular iron is connected to the steel pipe column to form the inner support lifting frame. S7, construction of the second concrete support: after the first concrete support is completely solidified, the foundation pit is further excavated to the second preset depth, the inner support lifting frame is further connected to the plurality of steel pipe columns, the pouring formwork is erected on the inner support lifting frame on both sides of the column, and the two ends of the pouring formwork are connected to the two supporting walls to form a second concrete inner support installation cavity, and the second concrete inner support installation cavity is injected with concrete, and the second concrete support is formed after the concrete is solidified. S8, installation of the steel pipe inner support: after the second concrete support is completely solidified, the foundation pit is further excavated to the third preset depth, the two ends of the steel pipe support structure are connected to the steel pipe columns on both sides of the column, and the steel pipe is connected to the steel pipe support structure, and the two ends of the steel pipe are connected to the two supporting walls to form the steel pipe inner support. S9, plugging of the supporting wall: after the steel pipe inner support is erected, the foundation pit is further excavated to the final depth; wherein the supporting wall includes the first supporting pile and the second supporting pile intersecting each other, and the intersection gap between the first supporting pile and the second supporting pile is plugged using a plugging structure.

[0006] The steel pipe column is a hollow structure, and the two ends of the steel pipe column along the length direction are respectively provided with a first connecting position and a second connecting position, and the two steel pipe columns are connected through the first connecting position and the second connecting position.

[0007] A river-proximal deep foundation pit construction method as described above, the sealing structure comprises a fastening steel plate, a reinforcing rib, a filling material; along the depth direction of the foundation pit, a plurality of reinforcing ribs are arranged at the intersection gap of the first support pile and the second support pile; one end of the reinforcing rib is connected to the first support pile, and the other end is connected to the second support pile; each intersection gap is provided with a fastening steel plate, and the fastening steel plates are sequentially connected to the plurality of reinforcing ribs at the intersection gap, and the fastening steel plates and the support wall form a sealed cavity, and the filling material is filled into the sealed cavity to seal the support wall.

[0008] A river-proximal deep foundation pit construction method as described above, the filling material is a leak stopper.

[0009] A river-proximal deep foundation pit construction method as described above, the steel disc is provided with a steel disc connecting hole for connecting the steel pipe column and a steel disc connecting part for connecting the first triangular iron; a plurality of first triangular irons are arranged on the steel pipe column and connected to the steel disc connecting part to support the steel disc.

[0010] A river-proximal deep foundation pit construction method as described above, in step S3, a grouting core pipe for injecting pure concrete is further arranged in the sleeve valve pipe, the sleeve valve pipe is provided with a grout overflow hole and a rubber sleeve for sectional grouting, the rubber sleeve is connected outside the grout overflow hole, and the concrete injected by the grouting core pipe overflows outside the sleeve valve pipe through the grout overflow hole.

[0011] A river-proximal deep foundation pit construction method as described above, the steel pipe support structure comprises a plurality of channel steels and a plurality of second triangular irons, the second triangular irons are oppositely connected to adjacent steel pipe columns for channel steel connection; a plurality of channel steels are arranged outside the column pile and connected to two adjacent steel pipe columns respectively to form a hoop member, and two mutually parallel channel steels extend outside the hoop member to form a steel pipe mounting position, and the steel pipe is connected to the steel pipe support structure through the steel pipe mounting position.

[0012] A river-proximal deep foundation pit construction method as described above, the steel pipe support structure further comprises a limiting member group for limiting the steel pipe, the limiting member group comprises a first limiting member and a second limiting member; the first limiting member and the second limiting member are respectively connected to two channel steels in the steel pipe mounting position for limiting.

[0013] A river-proximal deep foundation pit construction method as described above, a limiting bottom plate parallel to the steel pipe inner support is further arranged between the steel pipe columns; along the length direction of the steel pipe column, the limiting bottom plate is arranged on the lower side of the steel pipe inner support and connected to two adjacent steel pipe columns.

[0014] The method for constructing a deep foundation pit adjacent to a river comprises two adjacent steel pipe columns, each of which is provided with a first water stop plate and a second water stop plate, the first water stop plate and the second water stop plate are arranged in one-to-one correspondence on the two adjacent steel pipe columns, and the limiting bottom plate is fastened on the two adjacent steel pipe columns through the first water stop plate and the second water stop plate.

[0015] The method has the following beneficial effects: The method for constructing a deep foundation pit adjacent to a river has the following advantages: first, the bite type pile body structure of the supporting wall, the accurate grouting reinforcement based on radar detection outside the supporting wall and the curtain formation effectively improve the soil compactness and the anti-seepage performance, and greatly reduce the risk of river seepage; second, in combination with the layered excavation of the foundation pit and the construction method of the multi-channel internal support (concrete support and steel pipe support) of the supporting wall, stress balanced transmission and deformation control in the foundation pit excavation process are realized, and the stability of the overall supporting system is enhanced; meanwhile, the internal support lifting frame and the sectional formwork pouring process are adopted, the internal support construction precision and structural reliability are ensured, the anti-seepage performance, safety and reliability in the construction process are improved, the stability of the overall supporting system is improved, and the effect of saving materials is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 2 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 1 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 3 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 1 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 4 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 5 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 6 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 7 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 8 The structure of the part of the embodiment of the present application is hidden in the schematic diagram; Figure 9This is a schematic diagram of the steel pipe pile structure according to an embodiment of the present invention; Figure 10 This is a partial structural schematic diagram of the retaining wall according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the steel pipe column structure according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the sleeve valve tube installation according to an embodiment of the present invention.

[0018] In the diagram: 1-Retaining wall, 11-First retaining pile, 12-Second retaining pile, 13-Sealing structure, 131-Fastening steel plate, 132-Reinforcing rib, 133-Sealing cavity; 21-Sleeve valve pipe; 211-With overflow hole, 212-Rubber sleeve, 22-Grouting core pipe; 3-Column pile; 4-Steel pipe pile, 41-Steel pipe column, 411-First connection position, 412-Second connection position, 42-First waterstop plate, 43-Second waterstop plate; 5-Internal support support frame, 51-Steel disc, 511-Steel disc connection hole, 512-Steel disc connection part, 52-First triangular iron; 6-First concrete support; 7-Second concrete support Support; 81-steel pipe, 811-first connecting end, 812-second connecting end, 82-fixed end, 821-first fixed end connecting end, 822-second fixed end connecting end, 83-sliding end, 831-sliding end connecting part, 832-sliding head ejector rod, 833-sliding head hydraulic drive structure, 8331-sliding head adjusting limit protrusion, 834-sliding head limiting sleeve, 835-sliding head adjusting telescopic rod; 91-ring clamp, 911-channel steel, 92-second triangular iron, 93-steel pipe installation position, 941-first limiting component, 942-second limiting component; 10-limiting base plate. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1 to 12 As shown in the figure, this embodiment of the invention provides a method for constructing a deep foundation pit near a river, including the following steps: In this embodiment of the invention, the construction of the deep foundation pit along the river is carried out based on the fact that the retaining walls 1 on both sides of the foundation pit have been pre-constructed; S1, radar detection outside the foundation pit: use the radar car to scan and detect the soil around the supporting wall 1 outside the foundation pit, through the reflection signal of the electromagnetic wave emitted by the radar at the interface of different media, accurately judge whether there is cavity, loose layer and other adverse geological structure in the soil, avoid the collapse caused by soil disturbance during excavation, effectively enhance the safety during construction; S2, installation of column pile and steel pipe pile: after the radar detection and the soil condition are clear, a drill is used to drill column pile installation holes for installing column piles 3 and steel pipe pile installation holes for installing steel pipe piles 4 on both sides of the column pile installation holes, then an anchor rod machine is used to vertically place the steel reinforcement cage 31+lattice column 32 into the column pile installation hole, and the steel pipe column 41 into the steel pipe pile installation hole, and finally concrete is poured into the column pile installation hole and the steel pipe column 41 respectively, and after the concrete solidifies, the column pile 3 and the plurality of steel pipe piles 4 are formed respectively; S3, grouting reinforcement treatment outside the supporting wall: after the column pile and steel pipe pile construction is completed and the safety requirement is met, a drill is used to drill sleeve valve pipe installation holes in the soil according to the size of the sleeve valve pipe 21, the sleeve valve pipe installation holes are connected to each cavity in the predetermined depth direction, the sleeve valve pipe 21 is installed in the sleeve valve pipe installation hole, and the concrete is poured into each cavity of the soil outside the supporting wall 1 on both sides through the sleeve valve pipe 21 for reinforcement treatment, and a complete anti-seepage reinforcement curtain is formed; S4, excavation of foundation pit: after the soil outside the supporting wall is grouted and reinforced, the earthwork is excavated by mechanical excavation method, and the excavation sequence is determined according to the principles of "stratification, segmentation, symmetry, balance and timely", to ensure the normal excavation of the foundation pit; S5, construction of first concrete support: the pouring formwork is erected on both sides of the column pile 3, and the two ends of the pouring formwork are connected to the two sides of the supporting wall 1 to form a first concrete inner support installation cavity, and the concrete is poured into the first concrete inner support installation cavity, and after the concrete solidifies, the first concrete support 6 is formed; S6, production of inner support lifting frame: when the foundation pit is excavated to the first preset depth, the inner support lifting frame 5 is installed on the plurality of steel pipe columns 41, the steel disc 51 is welded to the pre-marked position outside the steel pipe column 41, the first triangular iron 52 is welded to the steel disc 51 on the side close to the ground along the length direction of the steel pipe column 41, and the other side of the first triangular iron 52 is welded to the steel pipe column 41 to form the inner support lifting frame 5; S7, construction of the second concrete support: after the first concrete support 6 is completely solidified, the foundation pit is continuously excavated to a second preset depth, the inner support jacking frame 5 is continuously connected on the plurality of steel pipe columns 41, the pouring formwork is arranged on the inner support jacking frame 5 on both sides of the column pile 3, and is connected to the two side support walls 1 to form a second concrete support installation cavity, the concrete is injected into the second concrete support installation cavity, and the second concrete support 7 is formed after the concrete is solidified; S8, installation of the steel pipe inner support: after the second concrete support 7 is completely solidified, the foundation pit is continuously excavated to a third preset depth, the two ends of the steel pipe support structure are welded on the steel pipe columns 41 on both sides of the column pile 3, and the steel pipe 81 is connected to the steel pipe support structure, and the two ends of the steel pipe 81 are connected to the two side support walls 1 to form the steel pipe inner support. S9, plugging of the support wall: after the steel pipe inner support is arranged, the foundation pit is continuously excavated to a final depth; wherein the support wall 1 comprises the first support pile 11 and the second support pile 12 intersecting with each other, and the intersection gap between the first support pile 11 and the second support pile 12 is plugged by using the plugging structure 13.

[0021] In the embodiment of the present application, the hidden geological hazards are preferentially identified by radar detection in S1, and the construction of the core vertical bearing structure (column pile 3, steel pipe pile 4) is completed in S2 before grouting and reinforcement in S3, which provides a stable internal support reference for subsequent grouting and excavation, forms a new reinforcement idea of “internal and external combination and internal fixation”, and significantly improves the safety in the construction process in the complex stratum near the river with high water level.

[0022] In the embodiment of the present application, the sleeve valve pipe installation holes are equidistantly arranged in the direction parallel to the support wall 1, and the arrangement interval is preferably 1200mm; the grouting depth of the sleeve valve pipe 21 is preferably 2m through the sand layer, so as to ensure that the concrete reinforced bodies formed by the cavities into which the concrete is injected are overlapped with each other, and a complete anti-seepage reinforcement curtain is formed, which not only can effectively reinforce the soil below the foundation pit bottom, but also can prevent the underground water from penetrating into the foundation pit through the sand layer to affect the stability of the foundation pit, thereby improving the safety and reliability in the construction process; in the embodiment of the present application, the diameter of the sleeve valve pipe 21 is preferably Φ48mm, so that the sleeve valve pipe 21 can be grouted for multiple times, and the grouting range of the sleeve valve pipe 21 is controllable, thereby effectively improving the stability in the construction process.

[0023] In the embodiment of the present application, the first concrete support 6 and the second concrete support 7 are made of reinforced concrete material, have high compressive strength and rigidity, and cooperate with the steel pipe inner support to effectively improve the support stability of the two side support walls 1.

[0024] Specifically, the steel pipe column 41 is designed as a hollow structure, and the two ends of the steel pipe column 41 along the length direction are respectively provided with a first connecting position 411 and a second connecting position 412, and two steel pipe columns 41 are connected through the first connecting position 411 and the second connecting position 412.

[0025] In the embodiment of the present application, four steel pipe columns 41 with a diameter of 168*10 mm are preferably arranged around the stand column pile 3 to ensure that the steel pipe column 41 cooperates with the stand column pile 3 to improve the support stability of the second concrete support 7; the first connecting position 411 is an external threaded connection part arranged outside the steel pipe column 41, and the second connecting position 412 is an internal threaded connection part arranged inside the steel pipe column 41; after the first steel pipe column 41 is installed in the steel pipe pile installation hole, the second connecting position 412 of the second steel pipe column 41 is rotated and installed outside the first connecting position 411 of the first steel pipe column 41 by a drilling machine, thereby effectively solving the problem that the two steel pipe columns 41 cannot be welded underground, and improving the convenience of installation of the steel pipe column 41 to ensure the stability of the steel pipe pile after forming.

[0026] Further, the plugging structure 13 includes a fastening steel plate 131, a reinforcing rib 132, and a filling material; a plurality of reinforcing ribs 132 are arranged at the intersection gap between the first support pile 11 and the second support pile 12 along the depth direction of the foundation pit; one end of the reinforcing rib 132 is connected to the first support pile 11, and the other end is connected to the second support pile 12; a fastening steel plate 131 is arranged at each intersection gap, and the fastening steel plate 131 is sequentially connected to the plurality of reinforcing ribs 132 at the intersection gap, and the fastening steel plate 131 and the support wall 1 form a sealed cavity 133, and the filling material is filled into the sealed cavity 133 to seal the support wall 1.

[0027] In the embodiment of the present application, the reinforcing rib installation hole for installing the reinforcing rib 132 is drilled in the first support pile 11 and the second support pile 12 respectively, and then the two ends of the reinforcing rib 132 are embedded and installed in the reinforcing rib installation hole of the first support pile 11 and the second support pile 12 respectively, so as to fasten the reinforcing rib 132 to the support wall 1; after the plurality of reinforcing ribs 132 are installed at the intersection gap between the first support pile 11 and the second support pile 12, the fastening steel plate 131 is welded on the plurality of reinforcing ribs 132 to achieve fastening, and then the filling material is filled into the sealed cavity 133 to seal the support wall 1, so as to avoid the support wall 1 being broken by excessive water pressure and improve the safety during construction.

[0028] Still further, the filling material is a leak stopper.

[0029] In the embodiment of the present application, since the leak stopper has the characteristics of fast setting, rapid growth of initial strength during hardening, micro-expansion and anti-permeability, by filling the leak stopper into the sealed cavity 133, it can be ensured that the filling material can quickly form an effective seal under the high water pressure environment near the river, thereby enhancing the waterproof performance of the support wall 1.

[0030] Further, the steel disc 51 is provided with a steel disc connecting hole 511 for connecting the steel pipe column 41, and a steel disc connecting part 512 for connecting the first triangular iron 52; the plurality of first triangular irons 52 are annularly arranged on the steel pipe column 41 and connected to the steel disc connecting part 512 to support the steel disc 51.

[0031] In the embodiment of the present application, the steel disc 51 is welded to the steel pipe column 41 through the steel disc connecting hole 511 to ensure the stability of the connection; in the embodiment of the present application, preferably, four first triangular irons 52 are arranged on each steel pipe column 41, and the four first triangular irons 52 are welded to the steel pipe column 41 at equal angles with the steel pipe column 41 as the center, and the upper end of the first triangular iron 52 is welded to the steel disc connecting part 512, so that the vertical load of the second concrete support 7 is effectively transmitted to the steel pipe column 41 through the first triangular iron 52, thereby ensuring the stability of the inner support jacking frame 5 under various working conditions, providing a solid and non-deformable working platform for the pouring of the second concrete support, and ensuring the forming quality of the concrete support.

[0032] Further, in step S3, the sleeve valve pipe 21 is further provided with a grouting core pipe 22 for injecting pure concrete, the sleeve valve pipe 21 is provided with a grout overflow hole 211 and a rubber sleeve 212 for sectional grouting, the rubber sleeve 212 is connected outside the grout overflow hole 211, and the concrete injected by the grouting core pipe 22 overflows outside the sleeve valve pipe 21 through the grout overflow hole 211.

[0033] In the embodiment of the present application, the sleeve valve pipe 21 cooperates with the grouting core pipe 22 and the grout overflow hole 211 with the rubber sleeve 212 to realize the repeatable and controllable sectional split grouting; during grouting, the rubber sleeve 212 opens the grout overflow hole 211 at a specific pressure to perform grouting; after the pressure dissipates, the rubber sleeve 212 closes to effectively prevent the backflow of concrete and the intrusion of surrounding soil particles to block the grout overflow hole 211, so that the specific depth of the soil can be reinforced multiple times, repeatedly and targeted, the grouting efficiency is high, and the curtain quality is good.

[0034] Further, the steel pipe support structure comprises a plurality of channel steels 911 and a plurality of second triangular irons 92, the second triangular irons 92 are oppositely connected to adjacent steel pipe columns 41 for welding of the channel steels 911; the plurality of channel steels 911 are annularly arranged outside the column pile 3 and respectively connected to adjacent two steel pipe columns 41 to form a hoop member 91, and two mutually parallel channel steels 911 extend out of the hoop member 91 and form a steel pipe mounting position 93, and the steel pipe 81 is connected to the steel pipe support structure through the steel pipe mounting position 93.

[0035] In the embodiment of the present application, the second triangular iron 92 is welded to the corresponding height position of the adjacent two steel pipe columns 41 for quick positioning and installation of the channel steel 911, so as to ensure the stress balance of the steel pipe 81 connected to the hoop member 24.

[0036] In the embodiment of the present application, preferably, four channel steels 911 are provided, and the two channel steels are perpendicular to each other and are welded to form a hoop member 91; two channel steels for connecting the lattice column abut against the column pile 3 and are fastened on the column pile 3 by welding, and the other two channel steels 911 for supporting the steel pipe 81 extend out of the hoop member 91 and form a steel pipe mounting position 93, and the steel pipe 81 is installed in the steel pipe mounting position 93 to limit the movement of the steel pipe 81 in the direction away from the bottom of the foundation pit and in the direction parallel to the supporting wall 1 under stress; In the embodiment of the present application, the steel pipe 81 can be connected on the steel pipe mounting position 93 by flange connection or welding connection; when the flange connection is adopted, the flanges are welded on the connection of the steel pipe 81, and the mating flanges are welded on the channel steels 911 extending out of the hoop member 91, so that the steel pipe 81 is quickly installed and disassembled by bolt connection, thereby ensuring the convenience of the flange connection; when the welding connection is adopted, the steel pipe 81 is directly welded on the two channel steels 911 extending out of the hoop member 91, and the welding connection is preferably adopted in the embodiment of the present application to improve the firmness and convenience of the connection.

[0037] Further, the steel pipe supporting structure further comprises a limiting member set for limiting the steel pipe 81, and the limiting member set comprises a first limiting member 941 and a second limiting member 942; the first limiting member 941 and the second limiting member 942 are respectively connected to the two channel steels 911 in the steel pipe mounting position 93 for limiting.

[0038] In the embodiment of the present application, the installation direction of the first limiting member 941 and the second limiting member 942 is parallel to the steel pipe column 41, and the first limiting member 941 and the second limiting member 942 are steel baffle plates; the two steel baffle plates are respectively vertically placed on the two channel steels extending out of the hoop member 91, and then the positions of the steel baffle plates are adjusted and the steel baffle plates are welded on the channel steels, so that the steel baffle plates can limit and reinforce the steel pipe 81 installed in the steel pipe mounting position 93, prevent the steel pipe 81 from moving during stress, and enhance the stability during construction.

[0039] Further, a limiting bottom plate 10 parallel to the steel pipe inner support is further provided between the steel pipe columns 41; along the length direction of the steel pipe column 41, the limiting bottom plate 10 is arranged on the lower side of the steel pipe inner support and is connected to two adjacent steel pipe columns 41.

[0040] In the embodiment of the present application, the limiting bottom plate 10 is a cement flat plate made of reinforced concrete material and is used for fastening the two adjacent steel pipe columns 41; along the length direction of the steel pipe column 41, the limiting bottom plate 10 is arranged on the lower side of the steel pipe 81 and is fixedly connected to the two adjacent steel pipe columns 41 by welding, so that the limiting bottom plate 10 can preliminarily ensure the perpendicularity of the steel pipe column 41, thereby improving the stability and reliability of the steel pipe 81 installation.

[0041] Further, the first water stop plate 42 and the second water stop plate 43 are respectively arranged on two adjacent steel pipe columns 41, and the first water stop plate 42 and the second water stop plate 43 are arranged one by one on two adjacent steel pipe columns 41, and the limiting bottom plate 10 is fastened on the two adjacent steel pipe columns 41 through the first water stop plate 42 and the second water stop plate 43.

[0042] In the embodiment of the application, the first water stop plate 42 and the second water stop plate 43 are both annular steel plates, and the annular steel plates are fixedly connected to the steel pipe column 41 at a preset height position through welding, the limiting bottom plate 10 is wrapped outside the first water stop plate 42 and the second water stop plate 43, so that the limiting bottom plate 10 can be fastened on the steel pipe column 41, and the underground water is prevented from seeping into the inside of the limiting bottom plate 10 through the water stop plate 27, thereby prolonging the service life of the limiting bottom plate 10.

[0043] In the embodiment of the application, the steel pipe inner support includes a steel pipe 81, a fixed end head for fastening the steel pipe 81, and a movable end head 83 for movably adjusting the steel pipe 81; the two ends of the steel pipe 81 are provided with a first connecting end 811 and a second connecting end 812 for mounting the steel pipe; one end of the fixed end head 82 and the movable end head 83 is respectively connected to the support wall 1 on both sides of the foundation pit, and the other end is respectively connected to the first connecting end 811 and the second connecting end 812.

[0044] The fixed end 82 is provided with a first fixed end connecting end 821 and a second fixed end connecting end 822. The first fixed end connecting end 821 is connected to the support wall 1 on one side of the foundation pit by a bolt, and the second fixed end connecting end 822 is provided for the first connecting end 811 to be threadedly connected, so as to improve the convenience of installation of the steel pipe inner support. The movable end 83 is provided with one of a screw adjusting mechanism or a hydraulic jacking mechanism. In the embodiment of the present application, the hydraulic jacking mechanism is preferred. The movable end 83 comprises a movable end connecting part 831, a movable head jacking rod 832, a movable head hydraulic drive structure 833, and a movable head limiting sleeve 834. The movable head hydraulic drive structure 833 is a hydraulic jacking mechanism. The movable end connecting part 831 is used for the second connecting end 812 to be threadedly connected and is fixed outside the movable head limiting sleeve 834. The movable head limiting sleeve 834 is slidably connected in the movable head hydraulic drive structure 833 relative to the other end of the movable end connecting part 831, so as to ensure that the movable end 83 can be extended and contracted. One end of the movable head jacking rod 832 is connected to the movable head limiting sleeve 834, and the other end is connected to the movable head hydraulic drive structure 833, so that the movable head limiting sleeve 834 is moved forward or backward through the extension and contraction of the movable head jacking rod 832, and the movable end connecting part 831 is moved along the length direction of the steel pipe 81, so that the movable end 83 can be used to fine-tune the length and pre-tightening force of the steel pipe 81, and the reliability of the steel pipe inner support is ensured. The other end of the movable head jacking rod 832 relative to the movable head hydraulic drive structure 833 is used to be threadedly connected with the support wall 1 on the other side of the fixed end, so as to improve the convenience of installation. In the embodiment of the present application, the movable head hydraulic drive structure 833 comprises a movable head adjusting limiting protrusion 8331, and the movable end 83 further comprises a movable head adjusting telescopic rod 835. The movable head adjusting limiting protrusion 8331 extends towards the movable end connecting part 831 and is slidably connected outside the movable head limiting sleeve 834, so as to limit the maximum sliding range of the movable end 83. One end of the movable head adjusting telescopic rod 835 is connected to the movable head limiting sleeve 834, and the other end is connected to the outside of the movable head hydraulic drive structure 833, so as to provide an additional horizontal support, and the accuracy of horizontal adjustment of the movable end 83 is ensured.

[0045] It should be understood that the terms "first", "second" and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and are not to be construed as limited to the order in which they are discussed. Furthermore, the terms "comprise", "include", "contain" and / or "have" should be understood as referring to the possibility that the object of the terms can comprise, include, contain and / or have other elements, not listed or implied, in addition to those explicitly described. It is also to be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", and the like, are used for convenience only and are not to be construed as indicating or implying relative or absolute position of an element to which they are used.

[0046] The above description is the preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can also make several improvements and variations, these improvements and variations are also considered the protection scope of the present application.

Claims

1. A method for constructing a deep foundation pit adjacent to a river, characterized in that, Includes the following steps: S1, Radar detection outside the foundation pit: The radar vehicle is used to scan and detect the soil outside the support wall (1) on both sides of the foundation pit in all directions. By the reflection signal generated by the electromagnetic wave emitted by the radar at the interface of different media, it is possible to accurately determine whether there are cavities, loose interlayers and other unfavorable geological structures inside the soil, so as to avoid soil disturbance and collapse during foundation pit excavation. S2, Installation of column piles and steel pipe piles: After completing radar detection and clarifying the soil conditions, drilling machines are used to drill column pile installation holes for installing column piles (3) at preset positions, and steel pipe pile installation holes for installing steel pipe piles (4) are drilled on both sides of the column pile installation holes. Then, anchor bolting machines are used to vertically place the steel cage (31) + lattice column (32) into the column pile installation holes, and the steel pipe column (41) is vertically placed into the steel pipe pile installation holes. Finally, concrete is injected into the column pile installation holes and the steel pipe column (41) respectively. After the concrete solidifies, column piles (3) and multiple steel pipe piles (4) are formed respectively. S3, Grouting reinforcement treatment on the outside of the retaining wall: After the construction of the column piles and steel pipe piles is completed and meets the safety requirements, the sleeve valve pipe installation hole is drilled in the soil according to the hole size of the sleeve valve pipe (21). The sleeve valve pipe installation hole is used to connect the cavities in the preset depth direction. The sleeve valve pipe (21) is installed in the sleeve valve pipe installation hole. Then, concrete is injected into the cavities of the soil outside the retaining wall (1) on both sides through the sleeve valve pipe (21) for reinforcement treatment, and a complete anti-seepage reinforcement curtain is formed. S4, Excavation of the foundation pit: After grouting and reinforcing the soil outside the retaining wall, the earthwork is excavated using mechanical excavation. The excavation sequence is determined according to the principles of "layering, segmentation, symmetry, balance, and timeliness" to ensure the normal progress of the foundation pit excavation. S5, Construction of the first concrete support: The casting template is erected on both sides of the column pile (3), and the two ends of the casting template are connected to the support wall (1) on both sides to form the first concrete inner support installation cavity. Concrete is injected into the first concrete inner support installation cavity, and the first concrete support (6) is formed after the concrete solidifies. S6, Fabrication of the inner support frame: When the foundation pit is excavated to the first preset depth, an inner support frame (5) is installed on multiple steel pipe columns (41). The steel disc (51) is connected to the pre-marked position on the outside of the steel pipe column (41). Along the length of the steel pipe column (41), one side of the first triangular iron (52) is connected to the side of the steel disc (51) near the ground, and the other side of the first triangular iron (52) is connected to the steel pipe column (41) to form the inner support frame (5). S7, Construction of the second concrete support: After the first concrete support (6) has completely solidified, the excavation pit is deepened to the second preset depth. Then, the inner support support frame (5) is connected to multiple steel pipe columns (41). The pouring template is erected on the inner support support frame (5) on both sides of the column pile (3) and connected to the support wall (1) on both sides to form the second concrete inner support installation cavity. Concrete is injected into the second concrete inner support installation cavity. After the concrete solidifies, the second concrete support (7) is formed. S8, installation of steel pipe inner support: after the second concrete support (7) is completely solidified, the foundation pit is continuously excavated to a third preset depth, two ends of the steel pipe support structure are connected to the steel pipe columns (41) on both sides of the column pile (3), then the steel pipe (81) is connected to the steel pipe support structure, and two ends of the steel pipe (81) are connected to the support walls (1) on both sides to form the steel pipe inner support; S9, plugging of the support wall: after the steel pipe inner support is erected, the foundation pit is continuously excavated to a final depth; wherein the support wall (1) comprises the intersecting first support pile (11) and the second support pile (12), and then the intersecting gap between the first support pile (11) and the second support pile (12) is plugged by using the plugging structure (13).

2. The method according to claim 1, wherein, The steel pipe column (41) is designed in a hollow structure, and first connecting positions (411) and second connecting positions (412) are arranged at two ends of the steel pipe column (41) in the length direction. Two steel pipe columns (41) are connected by the first connecting positions (411) and the second connecting positions (412).

3. The method according to claim 1, wherein, The plugging structure (13) comprises a fastening steel plate (131), a reinforcing rib (132) and a filling material. A plurality of reinforcing ribs (132) are arranged at the intersecting gap between the first support pile (11) and the second support pile (12) in the depth direction of the foundation pit. One end of the reinforcing rib (132) is connected to the first support pile (11), and the other end is connected to the second support pile (12). One fastening steel plate (131) is arranged at each intersecting gap, and the fastening steel plate (131) is sequentially connected to the plurality of reinforcing ribs (132) at the intersecting gap. The fastening steel plate (131) and the support wall (1) form a sealed cavity (133), and the filling material is filled into the sealed cavity (133) to seal the support wall (1).

4. The method according to claim 3, wherein, The filling material is leak-stopping agent.

5. The method according to claim 1, wherein, The steel disc (51) is provided with a steel disc connecting hole (511) for connecting the steel pipe column (41) and a steel disc connecting part (512) for connecting the first triangular iron (52). A plurality of first triangular irons (52) are annularly arranged on the steel pipe column (41) and connected to the steel disc connecting part (512) to support the steel disc (51).

6. The method according to claim 1, wherein, In step S3, a grouting core pipe (22) for injecting pure concrete is further arranged in the sleeve valve pipe (21). The sleeve valve pipe (21) is provided with a grout overflow hole (211) and a rubber sleeve (212) for sectional grouting. The rubber sleeve (212) is connected outside the grout overflow hole (211). The concrete injected by the grouting core pipe (22) overflows outside the sleeve valve pipe (21) through the grout overflow hole (211).

7. The method according to claim 1, wherein, The steel pipe support structure comprises a plurality of channel steels (911), a plurality of second triangular irons (92) connected to adjacent steel pipe columns (41) for connecting the channel steels (911); a plurality of channel steels (911) are arranged outside the column pile (3) and connected to two adjacent steel pipe columns (41) respectively to form a hoop member (91), and two mutually parallel channel steels (911) extend out of the hoop member (91) and form a steel pipe mounting position (93), and the steel pipe (81) is connected to the steel pipe support structure through the steel pipe mounting position (93).

8. The method according to claim 7, wherein, The steel pipe support structure further comprises a limiting member set for limiting the steel pipe (81), and the limiting member set comprises a first limiting member (941) and a second limiting member (942); the first limiting member (941) and the second limiting member (942) are connected to two channel steels (911) in the steel pipe mounting position (93) respectively to limit.

9. The method according to claim 1, wherein, The steel pipe columns (41) are further provided with a limiting bottom plate (10) parallel to the steel pipe inner support; along the length direction of the steel pipe column (41), the limiting bottom plate (10) is arranged on the lower side of the steel pipe inner support and connected to two adjacent steel pipe columns (41).

10. The method according to claim 9, wherein, Two adjacent steel pipe columns (41) are respectively provided with a first water stop plate (42) and a second water stop plate (43); the first water stop plate (42) and the second water stop plate (43) are arranged one by one on two adjacent steel pipe columns (41), and the limiting bottom plate (10) is fastened to two adjacent steel pipe columns (41) through the first water stop plate (42) and the second water stop plate (43).

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