CN-121992807-A - Composite stratum open cut foundation pit interface water control structure and construction method

CN121992807ACN 121992807 ACN121992807 ACN 121992807ACN-121992807-A

Abstract

The invention belongs to the technical field of building construction, and particularly discloses a water control structure of an interface of an open cut foundation pit of a composite stratum and a construction method, wherein the water control structure comprises a permeable stratum positioned at the upper layer of the foundation pit and a watertight stratum positioned at the lower layer of the foundation pit; vertical drain pipes are buried in the low-lying positions of the stratum interface, and two ends of each vertical drain pipe are respectively communicated with the water permeable blind pipe and the water collecting well. The method can solve the problem of interface water treatment at the interface position when the upper layer of the open cut foundation pit is a permeable stratum and the lower layer is a watertight stratum.

Inventors

DONG CHANGMING
LIU YING
LI XIANGLIN
WANG KAI
LUO GUILIN

Assignees

中铁隆工程集团有限公司
成都轨道建设管理有限公司

Dates

Publication Date: 20260508
Application Date: 20260326

Claims (10)

1. The water control structure for the composite stratum open cut foundation pit interface water comprises a permeable stratum positioned on the upper layer of a foundation pit and a watertight stratum positioned on the lower layer of the foundation pit, and is characterized in that a water collecting well is drilled at the bottom of the foundation pit, a permeable blind pipe arranged along the circumferential direction of the foundation pit is buried at the stratum interface between the permeable stratum and the watertight stratum, a vertical drain pipe is buried at the low-lying position of the stratum interface, and two ends of the vertical drain pipe are respectively communicated with the permeable blind pipe and the water collecting well.
2. The water treatment structure for the interface of the open cut foundation pit of the composite stratum according to claim 1, wherein a horizontal water diversion ditch is excavated at the bottom of the foundation pit, a horizontal water drain pipe communicated with the water collecting well is buried in the horizontal water diversion ditch, and the horizontal water drain pipe is communicated with the vertical water drain pipe and is used for introducing water discharged by the vertical water drain pipe into the water collecting well.
3. The water control structure of the composite stratum open cut foundation pit interface is characterized in that a cushion layer is arranged at the bottom of the foundation pit, a waterproof layer and a structural bottom plate are sequentially constructed on the upper surface of the cushion layer, and the water collecting well, the horizontal water diversion trench and the horizontal water drain pipe are all located below the cushion layer.
4. The water control structure for the composite stratum open cut foundation pit interface is characterized in that a water pump is arranged in the water collecting well, a ground drainage ditch is excavated on the ground of the foundation pit, a water pumping pipe is communicated between the ground drainage ditch and the water pump, and through holes for the water pumping pipe to pass through are formed in the structural bottom plate and the cushion layer.
5. The water control structure of the composite stratum open cut foundation pit interface according to claim 4, wherein a water stopping sleeve is arranged in the through hole, and the water pumping pipe penetrates through the water stopping sleeve.
6. The water control structure of the composite stratum open cut foundation pit interface according to any one of claims 1 to 5, wherein a plurality of water collecting wells are arranged, a plurality of water collecting wells are distributed at intervals, a plurality of vertical drain pipes are arranged, and a plurality of vertical drain pipes are distributed at intervals along the circumferential direction of the foundation pit.
7. A method for constructing water treatment at the interface of an open cut foundation pit of a composite stratum by using the water treatment structure of the interface of the open cut foundation pit of the composite stratum according to any one of claims 1 to 6, which is characterized by comprising the following steps: determining that the foundation pit is a composite stratum formed by a water permeable stratum on the upper layer and a water impermeable stratum on the lower layer; arranging a water collecting well in the foundation pit, determining the position of the water collecting well according to structural sections or blocks, and arranging a water pump in the water collecting well; A permeable blind pipe is buried in the stratum interface position of the permeable stratum and the impermeable stratum in a circumferential direction and is used for collecting interface water; Burying a vertical drain pipe at a low-lying position of a stratum interface of the permeable stratum and the impermeable stratum, and guiding interface water collected by the permeable blind pipe into a water collecting well at the bottom of the foundation pit; digging a horizontal water diversion ditch at the bottom of the foundation pit, and burying a horizontal drain pipe in the horizontal water diversion ditch for introducing water discharged by a vertical drain pipe into a water collecting well; and starting a water pump in the water collecting well to pump accumulated water in the well to the ground drainage ditch through the water pumping pipe.
8. The water treatment construction method for the composite stratum open cut foundation pit interface according to claim 7, wherein the side walls around the foundation pit are constructed with a sprayed concrete layer, and the permeable blind pipes and the vertical drain pipes which are embedded in the circumferential direction of the side walls of the foundation pit are arranged between the sprayed concrete layer and the foundation pit main body.
9. The method for water treatment construction at the interface of the open cut foundation pit of the composite stratum according to claim 7, wherein the water collection well is synchronously implemented in the construction stage of the foundation pit support structure, and precipitation is started before the foundation pit is excavated.
10. The method for water treatment construction at the interface of the open cut foundation pit of the composite stratum according to claim 7, wherein a water stopping sleeve is arranged at the water collecting well, and the well is sealed after the construction of the underground structure is completed.

Description

Composite stratum open cut foundation pit interface water control structure and construction method Technical Field The invention relates to the technical field of building construction, in particular to a water control structure of an open cut foundation pit interface of a composite stratum and a construction method. Background Before open cut foundation pit excavation and support construction, precipitation needs to be carried out in advance, but because of geological stratification reasons, the foundation pit cannot be in the same type of stratum, the upper part of the geological condition of part of the foundation pit is a permeable stratum with good water seepage performance such as mixed filling soil, sand pebbles and gravels, and the lower part of the geological condition of part of the foundation pit is a watertight stratum with poor water seepage performance such as compact clay, soft rock and hard rock, namely the composite stratum foundation pit. Interface water is reserved at the interface of two stratums, and is difficult to pump and drain cleanly through a dewatering well outside a foundation pit due to fluctuation of the stratums interface, water seepage phenomenon exists in the interface water area in the process of excavation and support of the foundation pit, water is generally guided through a cannula drainage mode in the prior art, water is not concentrated, drainage is incomplete, drainage pipe position waterproof plates cannot be paved continuously, foundation pit instability is caused due to water seepage of the side wall of the foundation pit, and further the foundation pit deformation collapse and water seepage of an underground structure are caused. Disclosure of Invention The invention provides a water control structure of an interface of an open cut foundation pit of a composite stratum and a construction method, and aims to solve the problem of interface position interface water treatment when the upper layer of the open cut foundation pit is a permeable stratum and the lower layer is a watertight stratum. The water control structure for the composite stratum open cut foundation pit interface is realized by the following technical scheme that the water control structure comprises a permeable stratum positioned at the upper layer of a foundation pit and a impermeable stratum positioned at the lower layer of the foundation pit, a water collecting well is arranged at the bottom of the foundation pit, a permeable blind pipe arranged along the circumferential direction of the foundation pit is buried at the stratum interface between the permeable stratum and the impermeable stratum, a vertical drain pipe is buried at the low-lying position of the stratum interface, and two ends of the vertical drain pipe are respectively communicated with the permeable blind pipe and the water collecting well. The scheme effectively solves the problem of interface water treatment at the interface position when the upper layer of the open cut foundation pit is a permeable stratum and the lower layer is a watertight stratum, the permeable blind pipe in the scheme can collect interface water generated at the interface position of the stratum, and the interface water collected by the permeable blind pipe is introduced into the water collecting well through the vertical drain pipe to be collected, and the water in the water collecting well is discharged in the later stage, so that scattered drainage in the foundation pit is avoided, and the technical problems of collection and discharge of the interface water of the foundation pit are solved. Further, the foundation pit bottom excavation has the horizontal water diversion ditch, the horizontal water diversion ditch is buried in the horizontal water diversion ditch and is linked together the horizontal drain pipe of sump pit, the horizontal drain pipe with vertical drain pipe intercommunication is used for with vertical drain pipe exhaust water is introduced the sump pit. The horizontal water diversion ditch of excavation in this scheme is arranged in installing horizontal drain pipe, and in the horizontal drain pipe can be with water tank drain pipe exhaust water smoothly leading to the sump pit, ensures that vertical water diversion pipe exhaust water can smoothly flow into the sump pit along predetermined route, avoids water to flow at the basement wantonly, realizes the orderly collection and the concentrated drainage of foundation ditch inside water. Further, the foundation pit bottom is provided with the bed course, the bed course upper surface has under construction waterproof layer and structure bottom plate in proper order, the sump pit the horizontal water diversion ditch with the horizontal drain pipe all is located the bed course below. All drainage structures in this scheme all are located below the bed course, do not occupy the space above the bed course, and the bed course can pour in succession, and the waterproof layer can be laid on the w