CN214993965U

CN214993965U - Dive sand cobble stratum foundation ditch back cover structure

Info

Publication number: CN214993965U
Application number: CN202023131451.9U
Authority: CN
Inventors: 李凯; 姬贺飞; 刘光磊; 武思宇
Original assignee: Zhongyan Technology Co Ltd
Current assignee: Zhongyan Technology Co Ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-12-03
Anticipated expiration: 2030-12-23

Abstract

The utility model discloses a submersible sandy gravel stratum foundation pit bottom sealing structure, which comprises a vertical waterproof curtain, a partition structure wall, an oblique grouting body, a vertical grouting body and an anti-seepage bottom plate; the vertical waterproof curtain is formed by a diaphragm wall, a filling pile, a stirring pile or grouting body, the partition structure wall is formed by a jet grouting pile, a stirring pile or grouting body, the oblique grouting body is formed by grouting in an oblique hole forming a certain angle with the ground, the vertical grouting body is formed by grouting in a hole vertical to the ground, and the oblique grouting body and the vertical grouting body form an anti-seepage bottom plate together. The utility model adopts inclined hole grouting, which can not only enlarge the plane projection range and increase the effective water plugging area, but also form inclined grouting body to limit the diffusion of the grout in four directions for the subsequent inclined grouting, thereby further improving the diffusion uniformity of the grout; in addition, the grouting body formed by oblique grouting can limit the diffusion of subsequent vertical grouting grout in three directions so as to improve the uniformity of grout diffusion.

Description

Dive sand cobble stratum foundation ditch back cover structure

Technical Field

The patent of the utility model relates to a dive sandy gravel stratum foundation ditch back cover structure belongs to building engineering stagnant water slip casting technical field.

Background

With the pace of the urbanization process in China being accelerated, the development and utilization of underground spaces are rapidly developed, foundation pit engineering is more and more common, and in the existing foundation pit excavation engineering of water-rich strata without obvious water barriers, four methods of precipitation, underwater concrete pouring, freezing and full-section grouting at the bottom of a foundation are generally adopted to solve the construction problem that the water level of underground water is higher than that of the bottom of the foundation pit.

The first dewatering method is that underground continuous wall, secant pile or drilled pile and corresponding waterproof curtain are used as maintenance structure, and after the maintenance structure is completed, inside and outside dewatering is performed, and after the underground water level is lowered to the designed water level, foundation pit excavation construction is performed. The method has the advantages of convenient construction, safety and reliability, but the precipitation can cause the problems of surrounding environment settlement and water resource waste to different degrees. For areas with scarce water resources and dense buildings, the method is gradually forbidden.

The second underwater concrete pouring method is to adopt an underground diaphragm wall, an occlusive pile or a drilled pile, a corresponding waterproof curtain and the like as maintenance structures, adopt plain concrete walls as partition walls, and then perform underwater concrete bottom plate pouring after underwater excavation to a designed depth. The method does not need precipitation, has little construction risk and little influence on the surrounding environment, but has large difficulty and high cost in underwater excavation and pouring construction and is not suitable for underground excavation foundation pit engineering.

The third freezing method is to freeze water in stratum by means of artificial refrigeration technology to change natural rock soil into frozen soil and increase its strength and stability for excavation under the protection of frozen wall. The method has the advantages of environmental protection, no pollution, short construction period, good effect, wide application range and the like, but has extremely high manufacturing cost.

The fourth foundation bottom full-section grouting means that firstly, an underground continuous wall, an occlusive pile or a drilled pile, a corresponding waterproof curtain and the like are adopted as maintenance structures, and then full-range grouting and water isolation are carried out at the bottom of a foundation pit. The method has the advantages of no need of precipitation, small construction risk and small influence on the surrounding environment, but the slurry diffusion is not easy to control, the effective utilization rate of the slurry is low, and the uniformity of the grouting effect cannot be ensured.

SUMMERY OF THE UTILITY MODEL

Problem to prior art existence, the utility model provides a dive sandy gravel stratum foundation ditch back cover structure solves present foundation ditch back cover structure cost high, influences the big and difficult control of slip casting back cover thick liquid diffusion, the inhomogeneous defect of grout effect of peripheral building.

A submerged sand-gravel stratum foundation pit bottom sealing structure comprises a vertical waterproof curtain, a partition structure wall, an oblique grouting body, a vertical grouting body and an anti-seepage bottom plate; the vertical waterproof curtain is formed by an underground diaphragm wall, a filling pile, a stirring pile, a rotary jet pile or grouting body, the partition structure wall is formed by the rotary jet pile, the stirring pile or the grouting body, the oblique grouting body is formed by grouting in an oblique grouting hole forming a certain angle with the ground, the vertical grouting body is formed by grouting in a vertical grouting hole which is vertical to the ground, and the oblique grouting body and the vertical grouting body form an anti-seepage bottom plate together. By adopting the inclined hole grouting mode, the plane projection range can be enlarged, the effective water plugging area is increased, and meanwhile, the formed inclined grouting body can limit the diffusion of the grout in four directions for the subsequent inclined grouting, so that the diffusion uniformity of the grout is further improved; in addition, the grouting body formed by oblique grouting can limit the diffusion of subsequent vertical grouting grout in three directions so as to improve the uniformity of grout diffusion.

The most close with this application scheme is dive sand cobble stratum foundation ditch back cover structure and construction process, and this scheme lies in adopting the slant slip casting with the biggest difference of this scheme, can carry out the construction arrangement according to foundation ditch real-time condition, and the construction is nimble, realizes the cementation of back cover many times of same vertical area, and the stagnant water effect is showing more, and under the same slip casting volume condition, the size increase is influenced in the haplopore horizontal action. Simultaneously, the water stopping device is combined with vertical grouting for use, and a better water stopping effect is achieved.

Contrast existing technology the utility model has the advantages of as follows and beneficial effect:

the utility model relates to a dive sand cobble stratum foundation ditch back cover structure can divide into a plurality of little regions with the foundation ditch through the divider wall that super jet grouting pile formed soon, and the divider wall has restricted the spread range of thick liquid in the plane, has avoided the thick liquid to flow away the emergence of phenomenon along fixed weak passageway, has improved the effective utilization ratio of thick liquid.

2 the utility model relates to a dive sand cobble stratum foundation ditch back cover structure, adopt the jet grouting technology to carry on the foundation ditch back cover than alone, can avoid because jet grouting draws the hole deflection and the thick liquid is diluted by rivers and erodees the problem that the seepage-proofing effect is not good that leads to, and have higher economic nature; compared with the single grouting full-section bottom sealing, the grouting full-section bottom sealing method has the advantages that the effective utilization rate of slurry can be improved, the anti-seepage effect and strength of the anti-seepage bottom plate are enhanced, the construction process is simplified, and the construction period is shortened; compared with the independent vertical grouting, the vertical grouting can provide the diffusion uniformity of the grout and enhance the integral seepage-proofing effect of the seepage-proofing bottom plate.

The utility model relates to a dive sand cobble stratum foundation ditch back cover structure, the machinery of use is all little and nimble, is applicable to open cut, undercut construction foundation ditch, and application scope is wide.

Based on the thought that the oblique grouting separation bottom plate space further limits the diffusion of grout, the combination mode of optimally designing the drilling position, the oblique grouting hole inclination angle, the oblique grouting and the vertical grouting according to different working conditions is all within the protection scope of the patent.

Drawings

The drawings herein are provided to further illustrate and, although not to limit, form a part of the present invention. In the drawings:

FIG. 1 is a top perspective view of the back cover structure of the present invention;

FIG. 2 is a cross-sectional view of the construction structure of the present invention;

FIG. 3 is a schematic view of a construction structure according to the present invention in the embodiment;

reference numbers and corresponding part names in the drawings:

the method comprises the following steps of 1-vertical waterproof curtain, 2-partition structure wall, 3-oblique grouting body, 4-vertical grouting body, 5-impermeable bottom plate, 6-I sequence oblique grouting hole, 7-II sequence oblique grouting hole, 8-I sequence vertical grouting hole, 9-II sequence vertical grouting hole, 10-water level and 11-upper soil covering.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Examples

The background of the embodiment is a subway station in Beijing, the station is constructed by a subsurface excavation reverse construction method, the length of the station is 317.6 meters, the width of the station is 25.3 meters, the height of the station is 16.87 meters, the top plate is covered with soil for 11.9 meters, the bottom plate of the station is located on a sand-gravel layer with strong water permeability, and the underground water line is located 5 meters above the bottom plate of the station.

As shown in fig. 1, a submersible sandy gravel stratum foundation pit bottom sealing structure is characterized by comprising a vertical waterproof curtain 1, a partition structure wall 2, an oblique grouting body 3, a vertical grouting body 4 and an impermeable bottom plate 5; the detailed structure of the station is shown in figure 3, and the specific design and construction steps are as follows:

(a) as shown in fig. 3, according to the hydrogeological conditions and the station size, the top buried depth of the waterproof curtain 1 is 11.9m, the bottom buried depth is 42.27m, the top buried depth of the partition structure 2 is 30.77 m, the bottom buried depth is 36.77m, the height is 6m, and the width is 1.5m, and the top buried depth of the drilling grouting sealing bottom layer 3 is 30.77 m, the bottom buried depth is 36.77m, and the thickness is 6 m.

(b) The waterproof curtain 1 is formed by secant piles with the diameter of 0.9m, and the secant thickness between the piles is 0.3 m; the division wall 2 is formed by occlusion of a high-pressure jet grouting pile with the diameter of 1.5m, and the occlusion thickness is 0.3 m.

(c) According to the design elevation and thickness of a foundation pit plane ruler and an anti-seepage bottom plate 5 and the depth of underground water level, the construction positions and deflection angles of a first-order oblique grouting hole 6 and a second-order oblique grouting hole 7, the construction positions of a first-order vertical grouting hole 8 and a second-order vertical grouting hole 9, the oblique hole intervals, the hole row intervals and the drilling lengths, the vertical hole intervals, the hole row intervals and the drilling lengths are determined.

(d1) And performing pipe following grouting from bottom to top by adopting cement-water glass double-liquid grouting, wherein the pipe lifting speed is 5cm/min, and performing I-sequence oblique grouting through an oblique grouting hole 6 to preliminarily form an oblique grouting body 3 in the figure 3.

(d2) After the first-order oblique grouting hole 6 is grouted for 3-5d, the second-order oblique grouting hole 7 is grouted to reinforce the oblique grouting body 3, so that the anti-seepage effect is improved, the grout adopts multi-ratio cement grout, the process adopts segmented grouting from bottom to top, and the distance between each segment is 0.5-1.5 m; the grouting end standard is determined by adopting a pressure flow double-limit method.

(d3) And performing pipe following grouting from bottom to top by adopting cement-water glass double-liquid grouting, wherein the pipe lifting speed is 5cm/min, and performing grouting on a vertical grouting hole 8 in the sequence I as shown in the figure 3 to initially form a vertical grouting body 4.

(d4) After the grouting of the I-sequence oblique grouting hole 8 is finished for 3-5d, grouting of the II-sequence vertical grouting hole 9 is carried out to reinforce the oblique grouting body 4, the anti-seepage effect is improved, the grout adopts multi-ratio cement grout, the process adopts segmented grouting from bottom to top, and the distance between each segment is 0.5-1.5 m; the grouting end standard is determined by adopting a pressure flow double-limit method.

(d5) Repeating the steps of d1, d2, d3 and d4 for the rest of the regions.

(e) And a dewatering well and a water level observation hole are arranged in each area to drain the underground water.

The above embodiments and descriptions are only used for explaining the technical solution of the present invention, and do not limit the protection scope of the present invention, and all modifications, replacements, and improvements are made within the principle of the present invention, which is included in the protection scope of the present invention.

Claims

1. A submerged sand-gravel stratum foundation pit bottom sealing structure is characterized by comprising a vertical waterproof curtain (1), a partition structure wall (2), an oblique grouting body (3), a vertical grouting body (4) and an anti-seepage bottom plate (5); the vertical waterproof curtain is formed by a diaphragm wall, a cast-in-place pile, a stirring pile, a rotary jet pile or grouting body, the partition structure wall (2) is formed by the rotary jet pile, the stirring pile or the grouting body, the oblique grouting body (3) is formed by grouting in the I-sequence oblique grouting hole (6) and the II-sequence oblique grouting hole (7), the vertical grouting body (4) is formed by grouting in the I-sequence vertical grouting hole (8) and the II-sequence vertical grouting hole (9), and the oblique grouting body (3) and the vertical grouting body (4) are completely filled in a cross mode within the range of a bottom sealing structure to form an impermeable bottom plate together; the partition structure wall (2) divides the foundation pit into a plurality of areas, and the inclined grouting body (3) divides each area bottom plate into narrower spaces, so that the diffusion range of the grout is further limited.

2. The bottom sealing structure of a foundation pit in a submersible sandy gravel stratum as claimed in claim 1, wherein the oblique grouting holes (6) of the I sequence and the oblique grouting holes (7) of the II sequence have certain intersection angles with the bottom surface of the foundation pit; the I-order vertical grouting holes (8) and the II-order vertical grouting holes (9) are vertical to the bottom surface of the foundation pit.