CN118048924A - Deep foundation pit bottom water seepage open drainage method - Google Patents

Abstract

The invention relates to the technical field of foundation pit construction, in particular to a deep foundation pit bottom water seepage and open drainage method, which comprises the steps of constructing a dewatering well between all two adjacent guard piles, then carrying out excavation construction on a region to be formed to form a current foundation pit, arranging a drain pipe on the side wall of the current foundation pit, continuing excavation construction on the current foundation pit to a preset elevation to form a pit bottom construction surface of the deep foundation pit, constructing a drainage ditch and a water collecting well on the side wall of the pit bottom construction surface close to the deep foundation pit, connecting the water collecting well and the dewatering well, and finally pumping accumulated water in the dewatering well out of the deep foundation pit.

Description

Deep foundation pit bottom water seepage open drainage method

Technical Field

The invention relates to the technical field of foundation pit construction, in particular to a deep foundation pit bottom water seepage and open drainage method.

Background

The soil retaining structure and the groundwater control and environmental protection measures required for ensuring the safety and stability of the underground space formed by excavating the ground downwards during the construction of the underground structure are called foundation pit engineering.

The foundation pit engineering is a system engineering integrating geological engineering, geotechnical engineering, structural engineering and geotechnical testing technology. The main content is as follows: engineering investigation, supporting structure design and construction, earth excavation and backfilling, groundwater control, informatization construction, surrounding environment protection and the like. The simplest and most economical method for foundation pit construction is to enlarge slope excavation, but is often limited by site conditions and surrounding environments, so that a support system is required to be designed to ensure smooth construction and better protect the surrounding environments.

In the prior art, when deep foundation pit construction is carried out, because accumulated water or underground water exists in the foundation pit, the defect that the excavation efficiency of the foundation pit is affected due to the fact that the excavation is difficult caused by accumulated water in the foundation pit during the foundation pit excavation construction is caused.

Disclosure of Invention

The invention mainly aims to provide a deep foundation pit bottom water seepage and open drainage method, which aims to solve the technical problems that in the related art, when a deep foundation pit is constructed, due to accumulated water or underground water exists in the foundation pit, the excavation is difficult due to accumulated water in the foundation pit during the excavation construction of the foundation pit, and the excavation construction efficiency of the foundation pit is affected.

In order to achieve the above purpose, in a first aspect, the present invention provides a deep foundation pit bottom water seepage and surface drainage method, which includes the following steps:

A dewatering well is arranged between all two adjacent fender piles; the dewatering well and two adjacent guard piles are arranged at intervals, and the depth of the dewatering well in the geological body is greater than that of the guard piles in the geological body;

Performing excavation construction on the area to be formed to form a current foundation pit;

A drain pipe is arranged on the side wall of the current foundation pit; wherein at least a portion of the drain pipe extends into the geologic volume of the sidewall of the current foundation pit;

continuing to excavate and construct the current foundation pit to a preset elevation to form a pit bottom construction surface of the deep foundation pit;

Continuing to connect the drain pipe to the pit bottom construction surface;

constructing a drainage ditch and a water collecting well at the side wall of the pit bottom construction surface close to the deep foundation pit; wherein the drainage ditch is communicated with the water collecting well, and the water collecting well is communicated with the dewatering well;

and pumping accumulated water in the dewatering well out of the deep foundation pit.

Optionally, the step of applying a precipitation well between all two adjacent fender piles comprises:

dividing the deep foundation pit into at least two excavation sections; wherein, each excavation section is internally provided with a plurality of fender piles which are sequentially arranged;

And in each excavation section, respectively applying one precipitation well between the two adjacent fender piles.

Optionally, the step of disposing a drain pipe on a side wall of the current foundation pit includes:

embedding a drain pipe in the side wall of the current foundation pit; wherein, the drain pipe is buried in the soil body by at least 50mm.

Optionally, after the step of embedding the drain pipe in the side wall of the current foundation pit, the method further includes:

drilling at least two drain holes on the pipe body of the drain pipe; wherein, the hole distance between every two adjacent water discharge holes is 5cm multiplied by 5cm;

a dense mesh net is wrapped on the pipe body of the drain pipe; wherein the mesh size of the dense mesh net is 50 meshes;

and performing interface pile net spraying construction on the side wall of the current foundation pit.

Optionally, the step of applying drainage ditches and water collection wells on the pit bottom construction surface near the side wall of the deep foundation pit comprises the following steps:

constructing a drainage ditch on the side wall of the pit bottom construction surface, which is close to the deep foundation pit; wherein the elevation of the ditch bottom of the drainage ditch is lower than the elevation of the construction surface of the pit bottom;

a blind pipe is buried in the drainage ditch;

backfilling construction is carried out on the drainage ditch by utilizing stones;

according to a preset interval, the water collection well is arranged at the side wall of the pit bottom construction surface, which is close to the deep foundation pit; wherein, the bottom elevation of the water collecting well is lower than the ditch bottom elevation of the drainage ditch.

Optionally, before the step of embedding the blind pipe in the drainage ditch, the method further comprises:

And a first geotechnical cloth layer is coated on the periphery of the blind pipe.

Optionally, the step of backfilling the drainage ditch by using stone comprises the following steps:

Backfilling the drainage ditch to the preset elevation by utilizing stones to form a backfill layer;

And paving a second geotechnical cloth layer on the surface of the backfill layer.

Optionally, in the step of applying the water collection well at a preset interval at a position where the pit bottom construction surface is close to the side wall of the deep foundation pit,

The preset distance is A, wherein A is more than or equal to 20m and less than or equal to 200m.

Optionally, the bottom-hole elevation of the dewatering well is C, and the bottom-hole elevation of the water collecting well is D, wherein c=d-3.5 m.

Optionally, before the step of applying the dewatering well between all two adjacent fender piles, the method further comprises:

And constructing a plurality of fender piles which are arranged at intervals in the region to be formed of the deep foundation pit.

The technical scheme of the invention has the following beneficial effects:

According to the technical scheme, a dewatering well is arranged between all two adjacent guard piles, then excavation construction is carried out on a region to be formed to form a current foundation pit, a drain pipe is arranged on the side wall of the current foundation pit, excavation construction is continued on the current foundation pit to a preset elevation, a pit bottom construction surface of a deep foundation pit is formed, a drainage ditch and a water collecting well are arranged on the side wall of the pit bottom construction surface close to the deep foundation pit, wherein the drainage ditch is communicated with the water collecting well, the water collecting well is communicated with the dewatering well, and finally accumulated water in the dewatering well is pumped out of the deep foundation pit.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of an illustrative deep foundation pit bottom water seepage and open drainage method;

fig. 2 is a flowchart of step S100 illustrated in fig. 1;

fig. 3 is a flowchart of step S300 illustrated in fig. 2;

fig. 4 is a flowchart of step S500 illustrated in fig. 1;

Fig. 5 is a flowchart of step S530 illustrated in fig. 4;

fig. 6 is a flow chart of some embodiments of the inventive examples.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the mechanisms in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicators are correspondingly changed.

In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

The inventive concept of the present invention is further elucidated below in connection with some embodiments.

The invention provides a deep foundation pit bottom water seepage and open drainage method, which comprises the following steps:

S100, constructing dewatering wells between all two adjacent fender piles; the dewatering well and two adjacent guard piles are arranged at intervals, and the depth of the dewatering well in the geological body is greater than that of the guard piles in the geological body;

S200, excavating and constructing the region to be formed to form a current foundation pit;

S300, arranging a drain pipe on the side wall of the current foundation pit; wherein at least a portion of the drain pipe extends into the geologic volume of the sidewall of the current foundation pit;

S400, continuing to excavate and construct the current foundation pit to a preset elevation to form a pit bottom construction surface of the deep foundation pit;

S500, constructing a drainage ditch and a water collecting well at the position, close to the side wall of the deep foundation pit, of the pit bottom construction surface; wherein the drainage ditch is communicated with the water collecting well, and the water collecting well is communicated with the dewatering well;

and S600, pumping accumulated water in the dewatering well out of the deep foundation pit.

In the embodiment, the dewatering well is arranged between all two adjacent guard piles, then the excavation construction is carried out on the region to be formed to form the current foundation pit, the drainage pipe is arranged on the side wall of the current foundation pit, the excavation construction is continued to the preset elevation of the current foundation pit, the pit bottom construction surface of the deep foundation pit is formed, the drainage ditch and the water collecting well are arranged on the side wall of the pit bottom construction surface close to the deep foundation pit, and finally the accumulated water in the dewatering well is pumped out of the deep foundation pit.

In some embodiments, step S100 includes:

S110, dividing the deep foundation pit into at least two excavation sections; wherein, each excavation section is internally provided with a plurality of fender piles which are sequentially arranged;

And S120, respectively constructing a dewatering well between the two adjacent fender piles in each excavation section.

In some embodiments, step S300 includes:

s310, embedding a drain pipe in the side wall of the current foundation pit; wherein, the drain pipe is buried in the soil body by at least 50mm.

In some embodiments, after step S310, further comprising:

S320, drilling at least two drain holes on the pipe body of the drain pipe; wherein, the hole distance between every two adjacent water discharge holes is 5cm multiplied by 5cm;

S330, a dense mesh net is wrapped on the pipe body of the drain pipe; wherein the mesh size of the dense mesh net is 50 meshes;

S340, performing interface pile net spraying construction on the side wall of the current foundation pit.

In some embodiments, step S500 includes:

S510, constructing a drainage ditch on the pit bottom construction surface close to the side wall of the deep foundation pit; wherein the elevation of the ditch bottom of the drainage ditch is lower than the elevation of the construction surface of the pit bottom;

s520, burying a blind pipe in the drainage ditch;

s530, backfilling construction is carried out on the drainage ditch by utilizing stones;

S540, according to a preset interval, the water collection well is constructed at the position, close to the side wall of the deep foundation pit, of the pit bottom construction surface; wherein, the bottom elevation of the water collecting well is lower than the ditch bottom elevation of the drainage ditch.

In some embodiments, prior to step S520, further comprising:

s550, wrapping a first geotechnical cloth layer on the periphery of the blind pipe.

In some embodiments, step S530 includes:

S531, backfilling the drainage ditch to the preset elevation by utilizing stones to form a backfill layer;

s532, paving a second geotechnical cloth layer on the surface of the backfill layer.

In some embodiments, in the step of applying the water collection well at a predetermined pitch at a position where the pit bottom construction surface is close to the side wall of the deep foundation pit,

The preset distance is A, wherein A is more than or equal to 20m and less than or equal to 200m.

In some embodiments, the dewatering well bottom hole elevation is C, and the water collection well bottom hole elevation is D, wherein c=d-3.5 m.

In some embodiments, before step S100, further includes:

and S700, constructing a plurality of fender piles which are arranged at intervals in the region to be formed of the deep foundation pit.

The traditional foundation pit dewatering adopts a pipe well dewatering and open drainage mode to treat, the well position of the dewatering well is more than or equal to 1.0m from the side line of the foundation pit, and the water level is required to be reduced to 1m of the substrate. The foundation pit base of the station is mostly positioned in a medium weathered mud stratum, only a small part of the foundation pit base is positioned in a pebble layer, the water inflow of the foundation pit reaches 17387m ³/d, and the depth is reduced by 34.7m. In order to ensure that the precipitation effect is obvious, the precipitation well setting of the foundation pit of the station is adjusted, and the open drainage measures are changed.

Setting a dewatering well: according to foundation ditch excavation segmentation, foundation ditch excavation direction, foundation ditch excavation each section afterbody circuit left and right side respectively set up 1 precipitation well and are located between the fender post, and the purpose is to guarantee that every section foundation ditch can find promptly after seeing the end and correspond the post-pile net and spout precipitation well, and precipitation well opening introduces the blind pipe, guarantees that basement open water becomes active water.

Seepage drainage of the side wall of the foundation pit: the station base is located the middle-weathering mud stratum, and mud rock pebble juncture seepage can appear in the foundation ditch excavation in-process, imbeds phi 50PVC water drain pipe before the construction of interface inter-pile net spray, and 50mm in the water drain pipe buries the soil body, and the surface punches, and hole distance is 5cm x 5cm, and the water drain pipe outsources 50 mesh dense mesh net and prevents gravel jam, drains to the foundation ditch bottom, directly discharges into the pit bottom sump pit.

Foundation pit open water drainage: after the foundation pit is excavated and the bottom is seen, a drain ditch with the width of 0.3m and lower than the bottom of the cushion layer is excavated in the foundation pit, a blind pipe with the outer wrapping geotechnical cloth of 250mm is buried in the drain ditch, and after the blind pipe is installed, pebbles or sand gravel are backfilled to the bottom of the cushion layer, and a layer of geotechnical cloth is covered above the blind pipe. The open water is drained to the constructed dewatering well, then the connection between the enclosure structure and the dewatering well is opened, the water is introduced into the dewatering well, and the dewatering well water pump is used for pumping and draining, so that the water is activated. The normal section is provided with a water collecting well at intervals of 20-25 m, the size of the water collecting well is 1m, the water collecting well is connected through a longitudinal drainage ditch and a transverse drainage ditch, accumulated water on the excavation surface is converged and flows into the water collecting well, accumulated water in the water collecting well is pumped and discharged out of a foundation pit through a water pump, the condition of no water on a substrate is achieved, and the concrete pouring quality of a station bottom plate is guaranteed.

The foregoing description is only of the optional embodiments of the present invention, and is not intended to limit the scope of the invention, and all the equivalent structural changes made by the description of the present invention and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the invention.

Claims (10)

1. The deep foundation pit bottom water seepage open drainage method is characterized by comprising the following steps of:

A dewatering well is arranged between all two adjacent fender piles; the dewatering well and two adjacent guard piles are arranged at intervals, and the depth of the dewatering well in the geological body is greater than that of the guard piles in the geological body;

Performing excavation construction on the area to be formed to form a current foundation pit;

A drain pipe is arranged on the side wall of the current foundation pit; wherein the drain pipe extends at least partially into the geological volume of the sidewall of the current foundation pit;

continuing to excavate and construct the current foundation pit to a preset elevation to form a pit bottom construction surface of the deep foundation pit;

Continuing to connect the drain pipe to the pit bottom construction surface;

constructing a drainage ditch and a water collecting well at the side wall of the pit bottom construction surface close to the deep foundation pit; wherein the drainage ditch is communicated with the water collecting well, and the water collecting well is communicated with the dewatering well;

and pumping accumulated water in the dewatering well out of the deep foundation pit.

2. The deep foundation pit bottom water seepage and open drainage method of claim 1, wherein the step of constructing a dewatering well between all adjacent two guard piles comprises the following steps:

dividing the deep foundation pit into at least two excavation sections; wherein, each excavation section is internally provided with a plurality of fender piles which are sequentially arranged;

and in each excavation section, respectively applying one precipitation well between two adjacent guard piles.

3. The deep foundation pit bottom water seepage and surface drainage method of claim 2, wherein the step of arranging a drain pipe on the side wall of the current foundation pit comprises the following steps:

embedding a drain pipe in the side wall of the current foundation pit; wherein, the drain pipe is buried in the soil body by at least 50mm.

4. The deep foundation pit bottom water seepage and open drainage method of claim 3, wherein after the step of embedding a drain pipe in the side wall of the current foundation pit, the method further comprises:

drilling at least two drain holes on the pipe body of the drain pipe; wherein, the hole distance between every two adjacent water discharge holes is 5cm multiplied by 5cm;

a dense mesh net is wrapped on the pipe body of the drain pipe; wherein the mesh size of the dense mesh net is 50 meshes;

and performing interface pile net spraying construction on the side wall of the current foundation pit.

5. The deep foundation pit bottom water seepage and open drainage method of claim 4, wherein the step of applying drainage ditches and water collection wells on the pit bottom construction surface near the side wall of the deep foundation pit comprises the following steps:

constructing a drainage ditch on the side wall of the pit bottom construction surface, which is close to the deep foundation pit; wherein the elevation of the ditch bottom of the drainage ditch is lower than the elevation of the construction surface of the pit bottom;

a blind pipe is buried in the drainage ditch;

backfilling construction is carried out on the drainage ditch by utilizing stones;

according to a preset interval, the water collection well is arranged at the side wall of the pit bottom construction surface, which is close to the deep foundation pit; wherein, the bottom elevation of the water collecting well is lower than the ditch bottom elevation of the drainage ditch.

6. The deep foundation pit bottom water seepage and open drainage method of claim 5, wherein before the step of embedding blind pipes in the drainage ditch, further comprising:

And a first geotechnical cloth layer is coated on the periphery of the blind pipe.

7. The deep foundation pit bottom water seepage and open drainage method of claim 5, wherein the step of backfilling the drainage ditch by using stone comprises the following steps:

Backfilling the drainage ditch to the preset elevation by utilizing stones to form a backfill layer;

And paving a second geotechnical cloth layer on the surface of the backfill layer.

8. The method of claim 5, wherein in the step of applying the water collecting well at a predetermined interval at a position where the pit bottom construction surface is close to the side wall of the deep foundation pit,

The preset distance is A, wherein A is more than or equal to 20m and less than or equal to 200m.

9. The deep foundation pit bottom water seepage and surface drainage method of claim 2, wherein the bottom elevation of the dewatering well is C, and the bottom elevation of the water collecting well is D, wherein c=d-3.5 m.

10. The deep foundation pit bottom water seepage and open drainage method of claim 2, wherein before the step of applying a dewatering well between all adjacent two fender posts, further comprising:

And constructing a plurality of fender piles which are arranged at intervals in the region to be formed of the deep foundation pit.