阅读说明：本技术 深基坑坑内降压井 (Depressurization well in deep foundation pit ) 是由 陆建生 刘中浩 沈驰 李璞 吴振华 王中兵 罗书省 于 2019-09-20 设计创作，主要内容包括：一种深基坑坑内降压井,涉及基建施工技术领域,所解决的是提高安全性的技术问题。该深基坑坑内降压井包括竖置在降压井孔内的降压井管,所述降压井管由上至下分为三个管段,其中的上管段为不透水的实管,中管段为透水的滤管,下管段为不透水的实管；所述降压井管与降压井孔之间的环形空间内由下至上依次填充有一层导水滤料、一层粘土球、一层微膨胀细石混凝土、一层粘土；并且导水滤料层的顶面高于降压井管的中管段；所述降压井管与降压井孔之间的环形空间内插设有注浆管,注浆管的下端管口伸入粘土球层的上部,注浆管的上端管口高于降压井管。本发明提供的降压井,适用于深基坑的施工。(A depressurization well in a deep foundation pit relates to the technical field of capital construction and solves the technical problem of improving safety. The depressurization well in the deep foundation pit comprises a depressurization well pipe vertically arranged in a depressurization well hole, wherein the depressurization well pipe is divided into three pipe sections from top to bottom, the upper pipe section is a watertight solid pipe, the middle pipe section is a permeable filter pipe, and the lower pipe section is a watertight solid pipe; a layer of water guide filter material, a layer of clay balls, a layer of micro-expansion fine stone concrete and a layer of clay are sequentially filled in an annular space between the depressurization well pipe and the depressurization well hole from bottom to top; the top surface of the water guide filter material layer is higher than the middle pipe section of the depressurization well pipe; and a grouting pipe is inserted into an annular space between the depressurization well pipe and the depressurization well hole, a pipe orifice at the lower end of the grouting pipe extends into the upper part of the clay ball layer, and a pipe orifice at the upper end of the grouting pipe is higher than the depressurization well pipe. The pressure reduction well provided by the invention is suitable for construction of a deep foundation pit.)

1. The utility model provides a step-down well in deep basal pit, includes erects the step-down well casing of putting in a step-down well bore, its characterized in that:

the pressure reducing well pipe is divided into three pipe sections from top to bottom, wherein an upper pipe section is a waterproof solid pipe, a middle pipe section is a permeable filter pipe, and a lower pipe section is a waterproof solid pipe;

a layer of water guide filter material, a layer of clay balls, a layer of micro-expansion fine stone concrete and a layer of clay are sequentially filled in an annular space between the depressurization well pipe and the depressurization well hole from bottom to top; the top surface of the water guide filter material layer is higher than the middle pipe section of the depressurization well pipe;

and a grouting pipe is inserted into an annular space between the depressurization well pipe and the depressurization well hole, a pipe orifice at the lower end of the grouting pipe extends into the upper part of the clay ball layer, and a pipe orifice at the upper end of the grouting pipe is higher than the depressurization well pipe.

2. The depressurization well in a deep foundation pit according to claim 1, wherein: a plurality of filler rib water stop plates are buried in the micro-expansion fine stone concrete, the filler rib water stop plates are annular plates, the filler rib water stop plates are arranged at intervals from bottom to top, the upper pipe section of the depressurization well pipe penetrates through the inner ring of each filler rib water stop plate, and the outer wall of the upper pipe section of the depressurization well pipe is fixedly connected with the inner ring edge of each filler rib water stop plate.

3. The depressurization well in a deep foundation pit according to claim 1, wherein: a plurality of water-absorbing expansion rubber rings which can expand after absorbing water are buried in the clay balls and the micro-expansion fine aggregate concrete, the water-absorbing expansion rubber rings are arranged at intervals from bottom to top, the upper pipe section of the depressurization well pipe penetrates through the inner rings of the water-absorbing expansion rubber rings, and the inner ring edges of the water-absorbing expansion rubber rings respectively abut against the outer wall of the upper pipe section of the depressurization well pipe.

Technical Field

The invention relates to a foundation construction technology, in particular to a technology of a depressurization well in a deep foundation pit.

Background

The lower part of the foundation pit is mostly a strong-permeability, quick-supply and high-water-head confined aquifer, once the wall of the depressurization well generates local defects and water is emitted, huge accident risks of the foundation pit can be caused, and huge adverse social effects and economic losses are caused.

Conventional step-down well all sets up clay ball and clay in the wall of a well periphery and comes the shutoff water, its shutoff effect receives clay ball quality, factor interference such as the closely knit quality of backfill, and be difficult to carry out effectual inspection, only can confirm whether there is the wall of a well situation of swamping in this stage after the foundation ditch excavation, and in case after the excavation, when the wall of a well appears the local passageway and swamps, at the high head, the passageway can enlarge rapidly under the fast velocity of flow state, and then form accident risk, therefore the security of conventional step-down well still remains to be improved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the depressurization well in the deep foundation pit with high operation safety.

In order to solve the technical problem, the invention provides a depressurization well in a deep foundation pit, which comprises a depressurization well pipe vertically arranged in a depressurization well hole, and is characterized in that:

the pressure reducing well pipe is divided into three pipe sections from top to bottom, wherein an upper pipe section is a waterproof solid pipe, a middle pipe section is a permeable filter pipe, and a lower pipe section is a waterproof solid pipe;

a layer of water guide filter material, a layer of clay balls, a layer of micro-expansion fine stone concrete and a layer of clay are sequentially filled in an annular space between the depressurization well pipe and the depressurization well hole from bottom to top; the top surface of the water guide filter material layer is higher than the middle pipe section of the depressurization well pipe;

and a grouting pipe is inserted into an annular space between the depressurization well pipe and the depressurization well hole, a pipe orifice at the lower end of the grouting pipe extends into the upper part of the clay ball layer, and a pipe orifice at the upper end of the grouting pipe is higher than the depressurization well pipe.

Furthermore, a plurality of reinforcement water stop plates are buried in the micro-expansion fine aggregate concrete, the reinforcement water stop plates are annular plates, each reinforcement water stop plate is arranged from bottom to top at intervals, the upper pipe section of the depressurization well pipe penetrates through the inner ring of each reinforcement water stop plate, and the outer wall of the upper pipe section of the depressurization well pipe is fixedly connected with the inner ring edge of each reinforcement water stop plate.

Furthermore, a plurality of water-absorbing expansion rubber rings which can expand after absorbing water are embedded in the clay balls and the micro-expansion fine aggregate concrete, the water-absorbing expansion rubber rings are arranged at intervals from bottom to top, the upper pipe section of the depressurization well pipe penetrates through the inner rings of the water-absorbing expansion rubber rings, and the inner ring edges of the water-absorbing expansion rubber rings respectively abut against the outer wall of the upper pipe section of the depressurization well pipe.

The invention provides a depressurization well in a deep foundation pit, which utilizes a water guide filter material to form a water guide structure at the periphery of a filter pipe, collects underground water in a water-containing soil layer into a depressurization well pipe, utilizes a compact clay layer formed by clay balls and micro-expansion fine stone concrete to separate the connection between a target water-containing layer outside the pipe wall of the depressurization well pipe and an upper soil layer, and fully utilizes the characteristics of heavy weight and compact expansion of the micro-expansion fine stone concrete, namely the micro-expansion fine stone concrete is used as a water-proof material and is also used as a water pressing material.

Drawings

FIG. 1 is a schematic structural diagram of a depressurization well in a deep foundation pit of a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a depressurization well in a deep foundation pit of a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of a depressurization well in a deep foundation pit of a third embodiment of the present invention.

Detailed Description

The following description will be made in detail with reference to the accompanying drawings, but the present invention is not limited thereto, and all similar structures and similar variations thereof adopted by the present invention shall fall within the protection scope of the present invention, wherein the pause numbers in the present invention shall represent the relation of the pause numbers, and the english letters in the present invention shall be distinguished by the case.

As shown in fig. 1, a depressurization well in a deep foundation pit according to a first embodiment of the present invention includes a depressurization well pipe vertically placed in a depressurization well hole, and is characterized in that:

the pressure reducing well pipe is divided into three pipe sections from top to bottom, wherein an upper pipe section 1 is a waterproof solid pipe, a middle pipe section 2 is a permeable filter pipe, and a lower pipe section 3 is a waterproof solid pipe;

a layer of water guide filter material 4, a layer of clay balls 5, a layer of micro-expansion fine stone concrete 7 and a layer of clay 8 are sequentially filled in an annular space between the depressurization well pipe and the depressurization well hole from bottom to top; the top surface of the water guide filter material layer is higher than the middle pipe section 2 of the pressure reducing well pipe;

and a grouting pipe 6 is inserted into an annular space between the depressurization well pipe and the depressurization well hole, a pipe orifice at the lower end of the grouting pipe 6 extends into the upper part of the clay ball layer, and a pipe orifice at the upper end of the grouting pipe 6 is higher than the depressurization well pipe.

In the first embodiment of the present invention, the micro-expanded fine aggregate concrete is a prior art, the micro-expanded fine aggregate concrete is formed by mixing stone particles and expanded concrete, and the particle size of the stone particles can be selected according to actual requirements.

When the construction of the first embodiment of the invention is carried out, the depressurization well pipe is firstly put down into the depressurization well hole, then the water guide filter material is firstly backfilled in the annular space between the depressurization well pipe and the depressurization well hole, so that the water guide structure is formed on the periphery of the middle pipe section (filter pipe) of the depressurization well pipe, then the clay ball is backfilled, the grouting pipe is embedded, after the backfilled clay ball layer is stabilized for 2 to 4 hours, the lower guide pipe is used for pouring the micro-expansion fine stone concrete, and then the clay is backfilled;

underground water in the target aquifer enters a middle pipe section (filter pipe) of the depressurization well pipe through a water guide structure formed by the water guide filter material, and partial sediments in the underground water are precipitated into a lower pipe section of the depressurization well pipe after entering the depressurization well pipe;

the clay ball can be dissolved into a compact clay layer under the action of underground water, has good water stopping effect, and can greatly reduce the permeation of the underground water in a lower aquifer to an upper soil layer under the barrier of the compact clay layer;

after the pressure reduction well pipe pumps water for a certain time, the water guide filter material layer and the compact clay layer (formed by clay balls) may sink to a certain degree, and then slurry can be poured at the lower end of the micro-expansion fine stone concrete by using a grouting pipe to fill in gaps between the compact clay layer and the micro-expansion fine stone concrete layer (the gaps are caused by the sinking of the water guide filter material layer and the clay ball layer); further ensuring the pipe wall stability of the later-stage depressurization well pipe, and avoiding the risk accidents caused by water overflow of the pipe wall;

the micro-expansion fine stone concrete can greatly improve the compactness between the micro-expansion fine stone concrete and an original soil layer of the hole wall of the pressure reducing well hole and the pipe wall of the pressure reducing well pipe through the micro-expansion characteristic, and simultaneously improves the anti-surge characteristic of confined water outside the pipe wall of the pressure reducing well pipe by utilizing the characteristic that the gravity of the micro-expansion fine stone concrete is far greater than that of the original soil layer; the uppermost clay layer can improve the anti-surge characteristic of the confined water outside the pipe wall of the pressure reducing well pipe through the self-gravity.

As shown in fig. 2, the second embodiment of the present invention is different from the first embodiment in that: in the second embodiment, a plurality of the reinforcing bar water stop plates 9 are buried in the micro-expansion fine stone concrete 7, the reinforcing bar water stop plates 9 are annular plates, the reinforcing bar water stop plates 9 are arranged at intervals from bottom to top, the upper pipe section 1 of the depressurization well pipe penetrates through the inner ring of each reinforcing bar water stop plate 9, and the outer wall of the upper pipe section 1 of the depressurization well pipe is fixedly connected with the inner ring edge of each reinforcing bar water stop plate 9.

In the second embodiment of the invention, the plurality of the filler rib water stop plates 9 are arranged in the micro-expansion fine-stone concrete 7, so that the micro-expansion fine-stone concrete 7 can expand towards the outer wall of the upper pipe section of the depressurization well pipe under the blocking of the filler rib water stop plates 9, the micro-expansion fine-stone concrete can be tightly attached to the outer wall of the upper pipe section of the depressurization well pipe, a concrete layer with higher local strength (close to one side of the depressurization well pipe) can be formed, and the sealing water stop performance between the micro-expansion fine-stone concrete and the upper pipe section of the depressurization well pipe is ensured.

As shown in fig. 3, the third embodiment of the present invention is different from the first embodiment in that: in the third embodiment, a plurality of water-absorbing expansion rubber rings 10 which expand after absorbing water are embedded in the clay ball 5 and the micro-expansion fine stone concrete 7, the water-absorbing expansion rubber rings 10 are arranged at intervals from bottom to top, the upper pipe section 1 of the depressurization well pipe passes through the inner ring of each water-absorbing expansion rubber ring 10, and the inner ring edge of each water-absorbing expansion rubber ring 10 abuts against the outer wall of the upper pipe section 1 of the depressurization well pipe.

In the third embodiment of the invention, the water-absorbing expansion rubber rings 10 are arranged in the clay ball 5 and the micro-expansion fine stone concrete 7, so that the compact clay layer formed by the clay ball 5 and the micro-expansion fine stone concrete 7 can be extruded and compacted by utilizing the characteristic that the water-absorbing expansion rubber rings 10 expand when meeting water, and the sealing water-stopping performance between the compact clay layer, the micro-expansion fine stone concrete layer and the upper pipe section of the pressure-reducing well pipe can be improved.