阅读说明：本技术 坑外抢险应急井施工方法 (Construction method of emergency well for emergency rescue outside pit ) 是由 陆建生 吴振华 李璞 刘中浩 沈驰 钱志兴 周亚宝 于 2019-09-27 设计创作，主要内容包括：一种坑外抢险应急井施工方法,涉及基建施工技术领域,所解决的是基坑应急抢险的技术问题。该方法先在井孔中下入一个护壁套管,利用护壁套管对井孔孔壁形成支撑；再在护壁套管内下放应急井管,应急井管的中管段是内置滤料的双层滤管,上管段及下管段均为不透水的实管；然后向应急井管与护壁套管之间的环形空间内回填滤料,使回填滤料的顶面高于应急井管的中管段；然后再将护壁套管提升至高于应急井管中管段且低于回填滤料的顶面的位置；再用固定夹具将应急井管的井口与护壁套管相互固定；即可实施抢险抽水；应急抢险结束后,再将应急井管、护壁套管依次向上拔出；然后再用回填粘土将井孔填平。本发明提供的方法,能快速打井、快速回收。(A construction method of an emergency well for emergency rescue outside a pit relates to the technical field of infrastructure construction, and solves the technical problem of emergency rescue of a foundation pit. Firstly, putting a wall protection casing in a well hole, and utilizing the wall protection casing to support the wall of the well hole; placing an emergency well pipe in the wall protection casing, wherein the middle pipe section of the emergency well pipe is a double-layer filter pipe with a built-in filter material, and the upper pipe section and the lower pipe section are both watertight solid pipes; then, backfilling a filter material into an annular space between the emergency well pipe and the protecting wall casing pipe, wherein the top surface of the backfilled filter material is higher than the middle pipe section of the emergency well pipe; then the wall protection casing is lifted to a position which is higher than the pipe section in the emergency well pipe and lower than the top surface of the backfill filter material; then fixing the wellhead of the emergency well pipe and the retaining wall casing pipe with a fixing clamp; the emergency water pumping can be implemented; after the emergency rescue is finished, the emergency well pipe and the wall protection sleeve are sequentially pulled out upwards; the wellbore is then filled with backfill clay. The method provided by the invention can be used for quickly digging a well and quickly recovering.)

1. A construction method of an emergency well for extra-pit emergency rescue is characterized by comprising the following specific steps:

1) selecting a watertight solid pipe as a wall protection casing pipe, drilling a well hole of an emergency well in soil at a target well position, putting the wall protection casing pipe into the well hole, and supporting the wall of the well hole by using the wall protection casing pipe and preventing slurry from rapidly seeping in the hole forming process;

two ways of drilling emergency well holes are available;

the first drilling mode is to press the wall protection casing pipe downwards into the soil body at the position of a target well, and then drill a well hole in the wall protection casing pipe;

the second drilling mode is that a drilling tool is used for drilling a well hole in the soil body of the target well position in a pipe following drilling mode, and when the well hole is drilled, the wall protection casing pipe is put down along with the drilling tool;

2) placing the emergency well pipe in the wall protection casing until the lower end of the emergency well pipe reaches the target position;

the emergency well pipe is divided into three pipe sections from top to bottom, wherein the upper pipe section is a waterproof solid pipe, the middle pipe section is a double-layer filter pipe with a built-in filter material, and the lower pipe section is a waterproof solid pipe;

3) backfilling a filter material in an annular space between the emergency well pipe and the protecting wall casing pipe, wherein the top surface of the backfilled filter material is higher than the middle pipe section of the emergency well pipe;

4) lifting the wall protection sleeve upwards until the lower end pipe orifice of the wall protection sleeve is higher than the middle pipe section of the emergency well pipe and is lower than the top surface of the backfill filter material;

5) fixing the wellhead of the emergency well pipe and the retaining wall casing pipe with a fixing clamp;

6) putting a water pump into the emergency well pipe, and pumping out water in the emergency well pipe;

7) after the emergency rescue is finished, pulling the emergency well pipe upwards from the wall protection sleeve;

8) pulling the retaining wall casing up from the borehole of the emergency well;

9) and backfilling clay into the well hole of the emergency well, and filling the well hole with the backfilled clay.

2. The method for constructing an emergency well for an out-of-pit emergency according to claim 1, wherein the emergency well hole is drilled in a manner of; the retaining wall casing is pressed down into the earth mass at the target well location and a borehole is drilled into the retaining wall casing.

3. The method for constructing an emergency well for an out-of-pit emergency according to claim 1, wherein the emergency well hole is drilled in a manner of; drilling a well hole in the soil body at the position of the target well by using a drilling tool in a pipe following drilling mode, and putting down the wall protection casing pipe in a following mode when drilling the well hole.

Technical Field

The invention relates to a capital construction technology, in particular to a technology of an off-pit emergency well construction method.

Background

The problem of underground water, particularly confined water, becomes a problem of frequent challenges in foundation pit engineering for subway construction, the problem of underground water is complex, the technical difficulty is high, the construction risk is high, once a large safety quality accident occurs, serious property loss or casualties are easily caused, and if emergency disposal is not timely, social public safety is even damaged.

In recent years, more and more foundation pit accidents are caused by improper underground water control, after some foundation pits have accidents, emergency dewatering wells are urgently needed to be drilled outside the pits, but due to the fact that barriers are more in the accident area, soil layer disturbance is large, hydraulic gradient is large and the like, normal well completion is difficult, and emergency rescue time is greatly delayed; meanwhile, when an emergency well is drilled outside the pit, the emergency well can be a barrier for later-stage construction in consideration of the possible construction of the later stage outside the pit; the sand content of the emergency well outside the pit such as water pumping cannot be effectively controlled, and obvious deformation risk is easy to occur around the well.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an off-pit emergency well construction method which can quickly set an emergency well and quickly recover the emergency well after the emergency.

In order to solve the technical problem, the invention provides an off-pit emergency well construction method, which is characterized by comprising the following specific steps of:

1) selecting a watertight solid pipe as a wall protection casing pipe, drilling a well hole of an emergency well in soil at a target well position, putting the wall protection casing pipe into the well hole, and supporting the wall of the well hole by using the wall protection casing pipe and preventing slurry from rapidly seeping in the hole forming process;

two ways of drilling emergency well holes are available;

the first drilling mode is to press the wall protection casing pipe downwards into the soil body at the position of a target well, and then drill a well hole in the wall protection casing pipe;

the second drilling mode is that a drilling tool is used for drilling a well hole in the soil body of the target well position in a pipe following drilling mode, and when the well hole is drilled, the wall protection casing pipe is put down along with the drilling tool;

2) placing the emergency well pipe in the wall protection casing until the lower end of the emergency well pipe reaches the target position;

the emergency well pipe is divided into three pipe sections from top to bottom, wherein the upper pipe section is a waterproof solid pipe, the middle pipe section is a double-layer filter pipe with a built-in filter material, and the lower pipe section is a waterproof solid pipe;

3) backfilling a filter material in an annular space between the emergency well pipe and the protecting wall casing pipe, wherein the top surface of the backfilled filter material is higher than the middle pipe section of the emergency well pipe;

4) lifting the wall protection sleeve upwards until the lower end pipe orifice of the wall protection sleeve is higher than the middle pipe section of the emergency well pipe and is lower than the top surface of the backfill filter material;

5) fixing the wellhead of the emergency well pipe and the retaining wall casing pipe with a fixing clamp;

6) putting a water pump into the emergency well pipe, and pumping out water in the emergency well pipe;

7) after the emergency rescue is finished, pulling the emergency well pipe upwards from the wall protection sleeve;

8) pulling the retaining wall casing up from the borehole of the emergency well;

9) and backfilling clay into the well hole of the emergency well, and filling the well hole with the backfilled clay.

Further, the emergency well hole is drilled in the mode of drilling; the retaining wall casing is pressed down into the earth mass at the target well location and a borehole is drilled into the retaining wall casing.

Further, the emergency well hole is drilled in the mode of drilling; drilling a well hole in the soil body at the position of the target well by using a drilling tool in a pipe following drilling mode, and putting down the wall protection casing pipe in a following mode when drilling the well hole.

According to the construction method of the emergency well outside the pit for emergency rescue, the wall protection sleeve is utilized to support and block water on the wall of the well hole, the problem that the hole cannot be formed due to factors such as soil layer disturbance and water flow channel can be avoided, surface layer obstacles can be eliminated through hole forming of the wall protection sleeve, and therefore the emergency well can be quickly arranged; the retaining wall sleeve pipe is used as a temporary hole-protecting structure, can be quickly pulled out and recovered after emergency rescue is finished, and is prevented from becoming a later-stage obstacle.

Drawings

Fig. 1 is a schematic structural view of an emergency well pipe in an off-pit emergency well construction method according to an 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, the construction method for the emergency well for the off-pit emergency provided by the embodiment of the invention is characterized by comprising the following specific steps:

1) selecting a watertight solid pipe as a wall protection casing pipe 4, drilling a well hole of an emergency well in soil at a target well position, putting the wall protection casing pipe 4 into the well hole, and supporting the wall of the well hole by using the wall protection casing pipe 4 and preventing slurry from rapidly seeping in the hole forming process;

two ways of drilling emergency well holes are available;

the first drilling mode is to press the retaining wall casing 4 downwards into the soil mass at the target well position, and then drill a well hole in the retaining wall casing 4, and the first drilling mode is suitable for the relatively soft soil mass;

the second drilling mode is that a drilling tool is used for drilling a well hole in the soil body of the target well position in a pipe following drilling mode, the wall protection casing pipe 4 is put down along with the drilling tool when the well hole is drilled, and the second drilling mode can be selected under the condition that the first drilling mode is difficult to implement;

2) lowering the emergency well pipe in the wall protecting casing 4 until the lower end of the emergency well pipe reaches the target position;

the emergency 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 double-layer filter pipe with a built-in filter material, and a lower pipe section 3 is a waterproof solid pipe;

3) backfilling a filter material 5 in an annular space between the emergency well pipe and the protecting wall casing 4, wherein the top surface of the backfilling filter material 5 is higher than the middle pipe section 2 of the emergency well pipe;

4) lifting the wall protection sleeve 4 upwards until the lower end pipe orifice of the wall protection sleeve 4 is higher than the middle pipe section 2 of the emergency well pipe, and the lower end pipe orifice of the wall protection sleeve 4 is lower than the top surface of the backfill filter material 5;

5) fixing the wellhead of the emergency well pipe and the retaining wall casing 4 by using a fixing clamp 6;

6) in the stage, the underground water in the target aquifer enters a middle pipe section 2 (a double-layer filter pipe with built-in filter materials) of the emergency well pipe through a backfilled filter material 5 and is collected in the emergency well pipe, partial sediments in the underground water are deposited into a lower pipe section 3 of the emergency well pipe after entering the emergency well pipe, and a water pump is placed in the emergency well pipe in the stage to pump out the water in the emergency well pipe;

7) after the emergency rescue is finished, the emergency well pipe is pulled out upwards from the wall protection sleeve 4;

8) pulling the retaining wall casing 4 up from the borehole of the emergency well;

9) and backfilling clay into the well hole of the emergency well, and filling the well hole with the backfilled clay.

The embodiment of the invention is used for emergency treatment of the foundation pit, is particularly suitable for the emergency treatment of the foundation pit with poor site conditions, can not be dug in a conventional precipitation well, and can be dug in a precipitation well with a large soil layer disturbance area, the hole forming efficiency can be quickly and effectively improved by utilizing the wall protection casing pipe, the well forming quality is improved, and meanwhile, the emergency well pipe and the wall protection casing pipe can be recovered in a green way.