CN-122013787-A - Foundation pit supporting structure in ultra-deep silt state and earth excavation construction method

CN122013787ACN 122013787 ACN122013787 ACN 122013787ACN-122013787-A

Abstract

The invention relates to the technical field of building construction, in particular to a foundation pit supporting structure in an ultra-deep silt state and an earthwork excavation construction method, comprising a foundation soil nailing wall, wherein the foundation soil nailing wall comprises a slope surface and a platform surface, a single-shaft stirring pile waterproof curtain is arranged below the platform surface, a reinforced soil body is arranged below the single-shaft stirring pile waterproof curtain at the bottom, and a positioning ring is arranged on the top surface of the platform surface; the water interception curtain construction method has the beneficial effects that the positioning ring is arranged on the platform surface, and the inner ring opening of the positioning ring clearly defines the area needing to be subjected to the construction of the single-shaft mixing pile serving as the water interception curtain. The plurality of conical heads fixed by the bottom surface of the lifting ring penetrate through the bottom plate of the positioning ring and then are inserted into the surface of the platform surface, the positioning ring is firmly limited on the platform surface, displacement of the positioning ring in the construction process is effectively avoided, accurate fixed-point limiting of construction of the single-shaft stirring pile as a water-interception curtain is achieved, construction quality of the water-interception curtain is guaranteed, and waterproof performance of a foundation pit is improved.

Inventors

SUN LIANG
CHU XIN
ZHENG WEI
YUAN XINGLEI
WANG ZIQIANG
HAN YOUHAI
LIAO BIN
LIN RUI

Assignees

中建八局第二建设有限公司
中建八局深圳建筑科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260316

Claims (8)

1. The foundation pit supporting structure in the ultra-deep silt state comprises a foundation soil nailing wall (1), wherein the foundation soil nailing wall (1) comprises a slope surface (101) and a platform surface (102), a single-shaft stirring pile waterproof curtain (2) is arranged below the platform surface (102), a reinforced soil body (3) is arranged below the single-shaft stirring pile waterproof curtain (2) at the bottom, and the foundation pit supporting structure is characterized in that a positioning ring (4) is arranged on the top surface of the platform surface (102), the positioning ring (4) is a convex circular ring plate, a lifting ring (5) is sleeved on the top of the positioning ring (4), a plurality of conical heads (501) are fixed on the bottom surface of the lifting ring (5), the conical heads (501) penetrate through the bottom plate of the positioning ring (4) and then are inserted on the surface of the platform surface (102), the top of the lifting ring (5) is rotationally connected with a threaded ring (6), and the threaded ring (6) is sleeved on the top of the foundation soil nailing wall (1).
2. The foundation pit supporting structure in the ultra-deep sludge state according to claim 1, wherein the bottom plate of the positioning ring (4) is provided with a plurality of through holes (401), the through holes (401) are in one-to-one correspondence with the conical heads (501), the height of the conical heads (501) is larger than the thickness of the bottom plate of the positioning ring (4), and the conical heads (501) are inserted into the top of the platform surface (102) after penetrating through the through holes (401).
3. The foundation pit supporting structure in an ultra-deep sludge state according to claim 2, wherein the conical head (501) is of a cylindrical structure, a conical structure is integrally formed at the bottom end of the conical head (501), a plurality of clamping grooves (502) are formed in a rod body of the conical head (501), the clamping grooves (502) are annular grooves, and the clamping grooves (502) are distributed in an up-down arrangement mode.
4. The foundation pit supporting structure in the ultra-deep sludge state according to claim 1, wherein the outer diameter of the lifting ring (5) is smaller than the outer diameter of a bottom plate of the positioning ring (4), a slot (503) is formed in the top surface of the lifting ring (5), the slot (503) is an annular groove, a connecting disc (601) is inserted into the slot (503), the connecting disc (601) is a convex annular plate, the top end of the connecting disc (601) is fixed to the bottom surface of the threaded ring (6), a baffle ring (504) is fixed to the inner annular surface and the outer annular surface of the slot (503) at a notch, and the two baffle rings (504) are different in size.
5. The foundation pit supporting structure in the ultra-deep silt state according to claim 1, wherein the inner ring surface of the screw joint ring (6) is provided with an inner thread, the top plate body of the positioning ring (4) is provided with an outer thread on the side wall, and the outer thread is connected with the inner thread in a matched manner.
6. The foundation pit supporting structure in the ultra-deep sludge state according to claim 1, wherein two elastic traction pieces (7) are fixed on the outer wall of the screw connection ring (6), the elastic traction pieces (7) are arc-shaped pieces, the two elastic traction pieces (7) are symmetrically distributed relative to the screw connection ring (6), a bottom groove (402) is formed in the outer ring of the bottom surface of the positioning ring (4), the bottom groove (402) is an annular groove, clamping strips (701) are integrally formed in the bottom end of the elastic traction pieces (7), the clamping strips (701) are arc strips with right trapezoid end faces, one side of each clamping strip (701) is inserted into the corresponding bottom groove (402), and pull rings (702) are fixed on the other side of the bottom end of each elastic traction piece (7).
7. The foundation pit supporting structure in an ultra-deep sludge state according to claim 1, wherein the screw joint ring (6) is provided with a plurality of grooves (602) at the outer ring of the top surface, the bottom surface of each groove (602) is provided with a reserved groove (603), a limiting shaft (604) is fixed between two parallel distributed side walls of each groove (602), a handle (605) is inserted into each groove (602), the limiting shaft (604) penetrates through one end of each handle (605), one end of each handle (605) is fixed with a rubber clamping strip (606), and the rubber clamping strips (606) are clamped between the handles (605) and the side walls of each groove (602) to generate elastic deformation.
8. An earth excavation construction method adopting the foundation pit supporting structure in the ultra-deep silt state as set forth in any one of claims 1 to 7, characterized in that the method comprises the following steps: According to the excavation depth of the foundation pit and the rock soil investigation report, the foundation pit is divided into two sections for slope release according to the foundation pit excavation depth and the rock soil investigation report, a platform surface (102) with the width of 1500mm is reserved between the primary slope and the secondary slope, single-shaft cement soil stirring piles are adopted to reinforce weak soil parts of the periphery of the foundation pit, pits in the pit and automobile ramps, foundation soil nailing walls (1) are arranged at the slope release positions for reinforcement, and positioning rings (4) are arranged on the platform surface (102) and used for constructing double-row single-shaft cement soil stirring piles.

Description

Foundation pit supporting structure in ultra-deep silt state and earth excavation construction method Technical Field The invention relates to the technical field of building construction, in particular to a foundation pit supporting structure in an ultra-deep silt state and an earthwork excavation construction method. Background In foundation pit construction in an ultra-deep silt state, many challenges are faced. Because the water content of the silt soil layer is extremely high, the situation of sliding of the side slope is extremely easy to occur in the excavation process, and serious threat is brought to the stability of the foundation pit. To prevent such problems, soil reinforcement is generally required, and uniaxial stirring piles are one of the usual reinforcement means. When the single-shaft stirring pile is adopted for soil reinforcement, dry operation is needed to ensure the construction quality of the stirring pile. Meanwhile, a single-shaft stirring pile is arranged at the slope-laying platform and used as a water interception curtain so as to prevent underground water from penetrating into the foundation pit, and the stirring piles are required to be mutually meshed in order to ensure the water interception effect. However, in the actual construction process, how to ensure that the single-shaft stirring pile can be accurately constructed as a water-interception curtain, and avoid the displacement of the positioning ring on the platform surface, thereby realizing fixed-point limiting is a problem to be solved urgently. If the positioning is inaccurate, loopholes can be caused on the water interception curtain, the waterproof effect of the foundation pit is affected, and then the safety and stability of the whole foundation pit engineering are affected. Disclosure of Invention The invention aims to provide a foundation pit supporting structure in an ultra-deep silt state and an earthwork excavation construction method, so as to solve the problems in the background technology. The foundation pit supporting structure comprises a foundation soil nailing wall, wherein the foundation soil nailing wall comprises a slope surface and a platform surface, a single-shaft stirring pile waterproof curtain is arranged below the platform surface, a reinforced soil body is arranged below the single-shaft stirring pile waterproof curtain at the bottom, a positioning ring is arranged on the top surface of the platform surface and is in a convex shape, a lifting ring is sleeved on the top of the positioning ring, a plurality of conical heads are fixed on the bottom surface of the lifting ring, the conical heads penetrate through the bottom plate of the positioning ring and are inserted into the surface of the platform surface, a screw ring is rotationally connected to the top of the lifting ring, and the screw ring is sleeved on the top end of the foundation soil nailing wall in a screw connection mode. Preferably, the bottom plate of the positioning ring is provided with a plurality of perforations, the perforations and the conical heads are in one-to-one correspondence, the height of the conical heads is larger than the thickness of the bottom plate of the positioning ring, and the conical heads are inserted into the top of the platform surface after penetrating through the perforations. Preferably, the conical head is of a cylindrical structure, the conical structure is integrally formed at the bottom end of the conical head, a plurality of clamping grooves are formed in the rod body of the conical head, the clamping grooves are annular grooves, and the clamping grooves are distributed in an up-down arrangement mode. Preferably, the external diameter of lift ring is less than the bottom plate external diameter of holding ring, and the slot has been seted up to the top surface of lift ring, and the slot is the ring channel, and the inside grafting of slot has the connection pad, and the connection pad is "protruding" font ring plate, and the bottom surface at the spiro union ring is fixed on the top of connection pad, and the interior anchor ring and the outer loop face of slot all are fixed with the backing ring in notch department, and two backing rings size are different. Preferably, the inner ring surface of the screw joint ring is provided with an internal thread, the top plate body of the positioning ring is provided with an external thread on the side wall, and the external thread is connected with the internal thread in a matching way. Preferably, the outer wall of the screw joint ring is fixed with two elastic traction pieces, the elastic traction pieces are arc-shaped pieces, the two elastic traction pieces are symmetrically distributed about the screw joint ring, a bottom groove is formed in the bottom surface of the positioning ring at the outer ring, the bottom groove is an annular groove, clamping strips are integrally formed in the bottom end of the elastic traction pieces and are arc-shaped str