CN213625645U

CN213625645U - Silt geological conditions's deep basal pit dewatering structure

Info

Publication number: CN213625645U
Application number: CN202021786754.1U
Authority: CN
Inventors: 宫宝军; 郭学太; 江浙飏; 王进; 孙华; 许政伟; 夏小斌
Original assignee: Zhejiang Provincial No 1 Water Conservancy & Electric Power Construction Group Holdings Co ltd
Current assignee: Zhejiang Provincial No 1 Water Conservancy & Electric Power Construction Group Holdings Co ltd
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2021-07-06
Anticipated expiration: 2030-08-25

Abstract

The utility model relates to a construction technical field, in particular to silt particle geological conditions's deep basal pit dewatering structure. The dewatering structure comprises a seepage interception wall cofferdam for enclosing the deep foundation pit and a plurality of dewatering deep wells arranged on the inner side of the seepage interception wall cofferdam, and the dewatering deep wells are positioned more than 5 meters on the inner side of the seepage interception wall cofferdam; the seepage intercepting wall cofferdam consists of a thin-wall plastic concrete seepage intercepting wall at the lower part and a cofferdam structure at the upper part, and the bottom of the thin-wall plastic concrete seepage intercepting wall and the bottom of the dewatering deep well both penetrate into a relative impervious layer below the bottom of the deep foundation pit; the deep dewatering well consists of a well pipe and a submersible pump arranged in the well pipe. Due to the combination of the thin-wall plastic concrete seepage-stopping wall weir-enclosing structure and the precipitation deep well, compared with the traditional underground seepage-stopping high-pressure rotary swing spray wall, the plastic concrete seepage-stopping wall has the advantages of higher seepage-stopping efficiency, better seepage-stopping effect, higher reliability and capability of greatly saving investment cost.

Description

Silt geological conditions's deep basal pit dewatering structure

Technical Field

The utility model relates to a construction technical field, in particular to silt particle geological conditions's deep basal pit dewatering structure.

Background

Along with the rapid development of hydropower construction, the scale of hydraulic engineering is continuously enlarged, the geological conditions of the hydraulic engineering are more and more complex, and the problem of early precipitation is usually involved when the construction is carried out under the complex geological conditions, particularly when deep foundation pit excavation is carried out. When a silt soil layer is constructed, due to the fact that the permeability coefficient of a water-bearing layer is large, when the excavation depth of a foundation pit is large and the underground water at the position is closely hydraulically connected with a nearby river channel, the aim of effectively reducing the underground water is difficult to achieve by arranging the dewatering well only.

If the precipitation effect can not be guaranteed, the construction conditions of the foundation pit dry land can be directly influenced, and the construction progress target is difficult to guarantee. How to safely and effectively reduce the underground water level and ensure that the dry land construction is the key for the smooth construction of the project. Therefore, it is necessary to develop a precipitation structure of a deep foundation pit for silty soil geological conditions.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the precipitation problem of deep basal pit when present complicated geological conditions is under construction, provide a complicated geological conditions's deep basal pit precipitation structure, through this kind of precipitation structure, can carry out precipitation operation for normal construction fast, guarantee going on smoothly of construction.

The utility model provides a technical scheme that its technical problem adopted is: a deep foundation pit dewatering structure for silt geological conditions comprises a seepage interception wall cofferdam for enclosing a deep foundation pit and a plurality of dewatering deep wells arranged on the inner side of a seepage interception wall cofferdam, wherein the dewatering deep wells are positioned more than 5 meters inside the seepage interception wall cofferdam; the seepage intercepting wall cofferdam consists of a thin-wall plastic concrete seepage intercepting wall at the lower part and a cofferdam structure at the upper part, and the bottom of the thin-wall plastic concrete seepage intercepting wall and the bottom of the dewatering deep well both penetrate into a relative impervious layer below the bottom of the deep foundation pit; the deep dewatering well consists of a well pipe and a submersible pump arranged in the well pipe.

Preferably, the thickness of the thin-wall plastic concrete seepage-stopping wall is 30-40cm, and the compressive strength of the plastic concrete is 3.0-5.0 MPa.

Preferably, the bottom of the thin-wall plastic concrete seepage-stopping wall extends into a relative impervious bed below the bottom of the deep foundation pit by more than 2 meters.

Preferably, the bottom of the precipitation deep well extends to the relative impervious bed below the bottom of the deep foundation pit by more than 1 meter.

Preferably, the pipe well pipe comprises an inner layer pipe, a filter screen is coated outside the inner layer pipe, a filter material is coated outside the filter screen, the inner layer pipe is formed by arranging sand settling pipes of common concrete pipes and water filter pipes of concrete sand-free pipes in a staggered mode, and the filter material is medium coarse sand.

Preferably, the bottommost layer of the inner layer pipe is a sand setting pipe of a common concrete pipe.

Preferably, the cofferdam structure is a clay cofferdam.

The utility model has the advantages that: due to the combination of the thin-wall plastic concrete seepage-stopping wall weir-enclosing structure and the precipitation deep well, compared with the traditional underground seepage-stopping high-pressure rotary swing spray wall, the plastic concrete seepage-stopping wall has the advantages of higher seepage-stopping efficiency, better seepage-stopping effect, higher reliability and capability of greatly saving investment cost. Meanwhile, on the premise that the foundation pit is enclosed by the seepage-stopping wall, the dewatering deep well can safely and effectively reduce the underground water level in the foundation pit, thereby ensuring the dry land construction conditions, ensuring the engineering construction progress and having remarkable economic and social benefits.

Drawings

Fig. 1 shows a schematic structural diagram of the present invention.

Fig. 2 is a sectional view of the deep well for precipitation according to the present invention.

In the figure: 1 cut-off wall cofferdam, 2 precipitation deep well, 3 thin-wall plastic concrete cut-off wall, 4 cofferdam structure, 5 tube well casing, 6 immersible pump, 7 inner layer pipe, 8 filter screen, 9 filter material, 10 sand setting pipe, 11 strainer pipe.

Detailed Description

Further refinements will now be made on the basis of the representative embodiment shown in the figures. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the embodiments as defined by the appended claims.

Specifically, referring to fig. 1 and 2, fig. 1 and 2 show a precipitation structure of a deep foundation pit under silt geological conditions, wherein the precipitation structure is mainly used for deep foundation pit construction under silt geological conditions. Because foundation pit development construction under silt geological conditions has abundant underground water, drainage operation needs to be carried out as soon as possible, and smooth construction can be guaranteed. Specifically, the precipitation structure comprises a seepage interception wall cofferdam 1 for enclosing the deep foundation pit, and then a plurality of precipitation deep wells 2 are arranged on the inner side of the seepage interception wall cofferdam 1, and the precipitation deep wells 2 are positioned more than 5 meters on the inner side of the seepage interception wall cofferdam 1; the seepage-stopping wall cofferdam 1 is composed of a thin-wall plastic concrete seepage-stopping wall 3 at the lower part and a cofferdam structure 4 at the upper part, and the cofferdam structure 4 is a clay cofferdam. The thickness of the thin-wall plastic concrete seepage-stopping wall 3 is 30-40cm, and the compressive strength of the plastic concrete is 3.0-5.0 Mpa; the bottom of the thin-wall plastic concrete seepage interception wall 3 and the bottom of the dewatering deep well 2 both extend into a relative impervious layer below the bottom of the deep foundation pit; the deep precipitation well 2 consists of a well pipe 5 and a submersible pump 6 arranged in the well pipe 5. The bottom of the thin-wall plastic concrete seepage-stopping wall 3 extends into the relative impervious bed below the bottom of the deep foundation pit by more than 2 meters.

The pipe well casing 5 comprises an inner layer pipe 7, a filter screen 8 is coated outside the inner layer pipe 7, a filter material 9 is coated outside the filter screen 8, the inner layer pipe 7 is formed by arranging sand setting pipes 10 of a common concrete pipe and water filter pipes 11 of a concrete sand-free pipe in a staggered mode, and the filter material 9 is medium coarse sand. The bottom layer of the inner layer pipe 7 is a sand setting pipe 10 of a common concrete pipe. Specifically, a sand setting pipe 10 is arranged on a watertight layer, and a water filtering pipe 11 is arranged on a water-bearing layer.

The lock for the vortex Mongolian hub construction project is positioned on a vortex channel, the lock is IV-level, a 500-ton ship lock is newly built, and the 1000-ton ship lock is considered. The check gate is a large (2) type water gate, is designed according to the gate passing flow rate of 2400m3/s in 20 years, is of an open structure, and adopts a gap pier type structure, two holes are connected in series, the total number of the two holes is 8, 16 holes are connected, the net width of a single hole is 10m, and the total overflowing width is 160 m. The ship lock foundation pit excavation depth is 18m, the check lock foundation pit excavation depth is 12m, and the foundation pit excavation depth is large. The stratum where the check lock and the ship lock are located is a silt soil layer, and according to hydrogeological data, underground water is abundant, the permeability coefficient of a water-bearing stratum is large, and the underground water is closely in hydraulic connection with nearby vortex rivers.

The engineering adopts a thin-wall plastic concrete seepage-stopping wall combined deep well precipitation structure, and specific definition is carried out on partial data of the structure according to geological conditions.

In this construction, the above-described precipitation structure is adopted. The structure protrudes that the thin-wall plastic concrete seepage-stopping wall is combined with a precipitation deep well to play a role together, and external sealing and internal drainage are realized.

The thin-wall plastic concrete seepage-stopping wall cofferdam consists of a lower thin-wall plastic concrete seepage-stopping wall and an upper cofferdam. The thin-wall plastic concrete seepage-stopping wall adopts a hydraulic continuous grab bucket to form a groove, the thickness is 40cm, the compressive strength of the plastic concrete is 3.0Mpa, the depth of the seepage-stopping wall is 30m, and the bottom of the seepage-stopping wall extends into a relative impervious bed by 2 m. And a clay cofferdam is arranged at the top of the seepage intercepting wall, the width of the cofferdam top is 3.0m, the height of the cofferdam top is 2.0m, and the slope ratio of the side slope is 1: 3. The thin-wall plastic concrete seepage-stopping wall forms a waterproof curtain underground, the inside and outside of the seepage-stopping wall are in hydraulic connection, and the cofferdam is tightly connected with the seepage-stopping wall to form an overground and underground seepage-stopping system.

And a dewatering deep well with the well depth of 28m is arranged in the seepage intercepting wall, and the bottom of the dewatering deep well is located on a relative impervious layer. The deep well for precipitation consists of a well pipe and a submersible pump, wherein the well pipe for the well for the precipitation consists of a common concrete pipe and a concrete sand-free pipe, the inner diameter D of the well pipe is =40cm, the wall thickness is 4cm, and the bore diameter D of the deep well is =90 cm. The bottommost section of the well pipe adopts a common concrete pipe as a sand setting pipe, and the aquifer corresponding to the well pipe adopts a concrete sand-free pipe as a filter pipe. The periphery of the filter pipe is provided with a filter screen and a filter material, the filter screen adopts 80-mesh and 60-mesh nylon filter screens, the filter material adopts medium coarse sand, water in the underground aquifer sequentially passes through the filter material, the filter screen and the filter pipe to enter the pipe well, and the underground water is discharged to a water discharge ditch outside the foundation pit through a submersible pump in the well.

In order to ensure the safety of underground water precipitation, the inside and outside of the seepage interception wall are provided with the pressure measuring pipes, the change condition of the underground water level is observed, and meanwhile, a specially-assigned person is arranged to regularly detect the sand content of the outlet water of the deep well, so that the requirement of relevant specifications is ensured to be met, and the underground water level in the foundation pit is effectively reduced on the premise of ensuring the safety of the foundation pit.

For purposes of explanation, specific nomenclature is used in the above description to provide a thorough understanding of the described embodiments. It will be apparent, however, to one skilled in the art that these specific details are not required in order to practice the embodiments described above. Thus, the foregoing descriptions of specific embodiments described herein are presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. It will be apparent to those skilled in the art that certain modifications, combinations, and variations can be made in light of the above teachings.

Claims

1. The utility model provides a silt geological conditions's deep basal pit dewatering structure which characterized in that: the dewatering structure comprises a seepage interception wall cofferdam (1) for enclosing the deep foundation pit and a plurality of dewatering deep wells (2) arranged on the inner side of the seepage interception wall cofferdam (1), and the dewatering deep wells (2) are positioned more than 5 meters on the inner side of the seepage interception wall cofferdam (1); the seepage intercepting wall cofferdam (1) consists of a thin-wall plastic concrete seepage intercepting wall (3) at the lower part and a cofferdam structure (4) at the upper part, and the bottom of the thin-wall plastic concrete seepage intercepting wall (3) and the bottom of the dewatering deep well (2) both penetrate into a relative impervious layer below the bottom of the deep foundation pit; the precipitation deep well (2) consists of a pipe well pipe (5) and a submersible pump (6) arranged in the pipe well pipe (5).

2. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the thickness of the thin-wall plastic concrete seepage-stopping wall (3) is 30-40cm, and the compressive strength of the plastic concrete is 3.0-5.0 Mpa.

3. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the bottom of the thin-wall plastic concrete seepage-stopping wall (3) extends into a relative impervious bed below the bottom of the deep foundation pit by more than 2 meters.

4. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the bottom of the precipitation deep well (2) extends into a relative impervious bed below the bottom of the deep foundation pit.

5. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the pipe well casing (5) comprises an inner layer pipe (7), a filter screen (8) is coated outside the inner layer pipe (7), a filter material (9) is coated outside the filter screen (8), the inner layer pipe (7) is composed of a sand settling pipe (10) of a common concrete pipe and a filter pipe (11) of a concrete sand-free pipe in a staggered arrangement mode, and the filter material (9) is medium coarse sand.

6. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the bottommost layer of the inner layer pipe (7) is a sand setting pipe (10) of a common concrete pipe.

7. The deep foundation pit dewatering structure for silt geological conditions according to claim 1, wherein: the cofferdam structure (4) is a clay cofferdam.