CN114809010B - Construction method of elevator shaft and foundation retaining wall of sump pit in easy-to-collapse soil - Google Patents

Abstract

The invention discloses a construction method of a lift shaft and a water pit foundation wall in easy collapse soil, which solves the problem of how to construct the lift shaft foundation and the surrounding wall of the water pit foundation in easy collapse quicksand soil; firstly, cast-in-place concrete is used for constructing a closed concrete retaining wall well wall outside the two pits on the pit bottom surface of the building foundation pit, namely a two pit shared open caisson, and the two pit shared open caisson is driven out to sink to the designed elevation of the elevator shaft foundation pit; and constructing a cast-in-place concrete template system of a pit bottom surface of the two pits sharing open caisson, wherein in the cast-in-place concrete template system of the pit outside sinking protection wall, an outer template which is abutted with three inner side surfaces in the pit outside concrete protection wall is formed, a foam board is adopted as an outer wall template, concrete is cast in situ, an inner sleeve open caisson is formed, and the construction of the elevator shaft and the pit foundation protection wall is completed through the secondary open caisson.

Description

Construction method of elevator shaft and foundation retaining wall of sump pit in easy-to-collapse soil

technical field

The invention relates to a building foundation construction method, in particular to a method for constructing elevator shaft foundations and surrounding retaining walls of sump foundations under easy-to-collapse soil conditions.

Background technique

The elevator shaft foundation and sump foundation of some high-rise buildings are designed to be adjacent to each other. The depth of the elevator shaft foundation pit is 1.8 meters, and the bottom surface of the sump pit foundation pit is 1.4 meters lower than the bottom surface of the elevator shaft foundation pit. The construction process of the foundation pit is as follows: first excavate the foundation pit to the design elevation of the building foundation, and then, at the bottom of the foundation pit at the design elevation of the building foundation, set out the opening of the elevator shaft foundation pit and the sump foundation pit. Excavate the location, then excavate the foundation pit of the elevator shaft foundation pit and the sump pit foundation pit, and use machine-made bricks to build bricks around the bottom of the foundation pit of the elevator shaft foundation pit and sump pit foundation pit after excavation Membrane, and plastered on the membrane of bricks for waterproofing, forming the surrounding walls of the foundation pit of the elevator shaft and the foundation pit of the sump pit, and building the concrete foundation of the elevator shaft and the concrete foundation of the sump pit in the surrounding walls constructed; But, when continuing to dig the elevator shaft foundation pit and the sump pit foundation pit in the building body foundation pit, sometimes encounter the quicksand soil and groundwater that are easy to collapse, and continue to dig the elevator shaft foundation pit and the sump pit foundation pit. During the foundation pit, the soil collapsed severely, making it difficult to form the foundation pit; how to construct the surrounding walls of the elevator shaft foundation and the concrete foundation of the sump pit became a problem that needed to be solved on site.

Contents of the invention

The invention provides a construction method for an elevator shaft and sump foundation retaining walls in easy-to-collapse soil, and solves the technical problem of how to construct the elevator shaft foundation and surrounding retaining walls of the sump foundation in easy-to-collapse quicksand soil.

The present invention solves the above technical problems through the following technical solutions:

The general idea of the present invention is: on the bottom surface of the foundation pit of the building body, first cast-in-situ concrete is constructed to construct the closed concrete retaining wall well wall on the outside of the second pit, that is, the common caisson of the second pit, and the soil below the common caisson of the second pit is taken out. The common caisson of the second pit is sunk to the design elevation of the foundation pit of the elevator shaft; then, the soil in the common caisson of the second pit is cleaned, and the outer sinking wall of the sump is constructed on the bottom of the common caisson of the second pit In the cast-in-place concrete formwork system for sinking the retaining wall well wall outside the sump, the outer formwork that abuts with the three inner sides of the outer concrete retaining wall well wall of the second pit uses foam As the formwork of the outer wall, concrete is poured on site to form the outer concrete wall of the sump, that is, the inner caisson, and the cast-in-place concrete formwork system for the sinking of the outer wall of the sump is removed. The template is burnt with a blowtorch, so that the outer wall of the inner caisson is separated from the inner wall of the common caisson of the second pit, and the inner caisson is sunk to the pit of the sump by pulling out the soil below the inner caisson At the design elevation of the bottom, the construction of the elevator shaft and the foundation wall of the sump pit is completed through the secondary caisson.

A method for constructing elevator shaft and sump foundation retaining wall in easy-to-collapse soil, in which an elevator shaft foundation pit and a sump pit foundation pit connected together are designed in the foundation pit of the building body, characterized in the following steps:

Step 1. On the bottom surface of the foundation pit of the building body, set out the construction outline of the pre-set elevator shaft foundation pit and the second pit outside the second pit of the sump foundation pit;

The second step is to set up a cast-in-place concrete formwork system for the sinking wall of the outer wall of the second pit on the construction contour of the outer closed wall of the second pit, and pour concrete to form the outer concrete wall of the second pit;

The third step is to dig out the soil below the outer concrete retaining wall of the second pit, so that the outer concrete retaining wall of the second pit will sink to the design elevation of the foundation pit of the elevator shaft by its own gravity; Excavate the soil in the outer concrete retaining wall of the second pit in place to form the bottom of the foundation pit of the elevator shaft;

Step 4: On the bottom surface of the foundation pit of the elevator shaft, set out the construction outline of the closed retaining wall outside the foundation pit of the pre-set sump pit. The inner side of the retaining wall, that is, the three sides in the construction outline of the outer retaining wall of the rectangular sump are abutted against the three inner sides of the outer concrete retaining wall of the second pit;

The fifth step is to set up the cast-in-place concrete formwork system of the sinking wall and well wall outside the sump on the construction contour of the outer retaining wall of the sump, and set up the cast-in-place concrete formwork system of sinking the retaining wall and well wall outside the sump , the outer formwork that abuts against the three inner sides of the outer concrete wall of the second pit uses foam boards;

The sixth step is to pour concrete in the cast-in-place concrete formwork system for sinking the retaining wall well wall outside the sump pit to form a closed concrete retaining wall well wall outside the sump pit;

The seventh step is to remove the formwork in the cast-in-situ concrete formwork system of the sinking wall and well wall on the outside of the sump pit, and use a blowtorch to abut the foam on the three inner sides of the concrete wall on the outside of the second pit The plate is burnt out, and there is a gap between the two caissons between the outer concrete wall of the sump and the outer concrete wall of the second pit;

Step 8: Take out the soil below the concrete retaining wall on the outside of the sump, so that the concrete retaining wall on the outside of the sump sinks to the design elevation of the foundation pit of the sump by its own gravity. Excavate the soil in the concrete retaining wall outside the sump pit to form the bottom of the sump pit foundation pit;

Step 9: In the interval gap between the two caissons between the top surface of the concrete retaining wall well wall outside the sump that has sunk in place and the bottom end surface of the concrete retaining wall well wall outside the second pit, set a cement slurry pouring layer, and place the two Well interval gap sealing;

Step 10: On the bottom of the foundation pit of the elevator shaft foundation and the bottom of the foundation pit of the sump pit, respectively construct a 200 mm thick sandstone cushion, and arrange drainage pipes.

The height of the concrete retaining well wall outside the second pit is 1.8 meters, and the height of the concrete retaining wall well wall outside the sump pit is 1.4 meters; The strength is the same, and the concrete strength in the cement paste pouring layer is one level higher than that in the concrete wall well wall outside the second pit.

In the present invention, the caissons are poured on site twice successively, and the caissons are carried out in stages to solve the problems of quicksand and collapse encountered when excavating foundation pits. The two caissons also serve as structural side walls, which improves the construction quality while , also saves cost; especially, the foam board is set between the two caissons, which is used as the outer formwork for the inner caisson to be concreted, and the inner caisson is formed and before it sinks, it is burned off with a blowtorch The method solves the problem that the sliding friction force between the two caisson walls is too large during the sinking process of the inner casing caisson, which affects the normal sinking of the inner casing caisson.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of setting the outer concrete retaining wall shaft wall 3 of the second pit before sinking on the foundation pit bottom surface of the building body foundation pit 1;

Fig. 3 is a structural schematic diagram when the outer concrete retaining wall 3 of the second pit is sunk in place;

Fig. 4 is a structural schematic diagram in the direction of looking down when the concrete retaining wall well wall 3 outside the second pit sinks in place;

Fig. 5 is the structure schematic diagram of the cast-in-place concrete formwork system 6 and the concrete retaining wall well wall 7 outside the sump pit outside the sinking pit wall built on the bottom surface 4 of the elevator shaft foundation pit;

Fig. 6 is a structural schematic diagram of the cast-in-place concrete formwork system 6 of the sinking retaining wall well wall outside the sump pit and the concrete retaining wall well wall 7 outside the sump pit in the direction of looking down;

Fig. 7 is a schematic diagram of the structure when the concrete retaining wall 7 outside the sump sinks in place.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing:

A method for constructing elevator shaft and sump foundation retaining walls in easy-to-collapse soil, in which the elevator shaft foundation pit and sump foundation pit connected together are designed in the foundation pit 1 of the building body, that is, a rectangular elevator shaft The well foundation pit and the rectangular sump foundation pit are arranged side by side to form a large rectangle, which is characterized by the following steps:

Step 1: On the bottom surface of the foundation pit 1 of the building body, set out the construction outline 2 of the closed retaining wall outside the second pit of the foundation pit of the elevator shaft and the foundation pit of the sump pit, that is, draw two parallel Outer large rectangular outline of the foundation pit;

The second step is to set up a cast-in-place concrete formwork system for the sinking wall of the outer wall of the second pit on the construction outline 2 of the outer closed wall of the second pit, and pour concrete to form the outer concrete wall of the second pit and the wall 3, which is shared by the second pit caisson;

The 3rd step, the soil body below the concrete retaining wall shaft wall 3 outside the second pit is pulled out, and the concrete retaining wall shaft wall 3 outside the second pit is sunk to the design elevation position of the elevator shaft foundation pit by its own gravity; Excavate the soil in the outer concrete retaining wall 3 of the second pit that has sunk in place to form the bottom 4 of the foundation pit of the elevator shaft;

Step 4: On the bottom surface 4 of the foundation pit of the elevator shaft, set out the construction outline 5 of the closed retaining wall outside the foundation pit of the pre-set sump pit, that is, draw the outline of the concrete building of the inner caisson. The construction outline 5 of the outer retaining wall of the water pit is abutted against the inner side of the concrete retaining wall well wall 3 outside the second pit, that is, the three sides of the building outline 5 of the rectangular sump outer retaining wall are the same as the outer concrete retaining wall of the second pit. The three inner sides of the shaft wall 3 are abutted together, that is, the precast inner caisson has three outer sides that are abutted against the inner side of the common caisson of the second pit;

The fifth step, on the construction outline 5 of the outer retaining wall of the sump, set up the cast-in-place concrete formwork system 6 for sinking the retaining wall and well wall outside the sump, and sink the cast-in-place concrete formwork for the retaining wall and well wall outside the sump In system 6, foam boards are used for the outer formwork that abuts the three inner sides of the outer concrete wall 3 of the second pit;

In the sixth step, in the cast-in-situ concrete formwork system 6 for sinking the retaining wall well wall outside the sump pit, pour concrete to form a closed concrete retaining wall well wall 7 outside the sump pit, that is, the concrete retaining wall well wall 7 outside the sump pit ( Inner casing caisson) is socketed in the outer concrete wall 3 of the second pit (the second pit shares the caisson);

The seventh step is to remove the formwork in the cast-in-place concrete formwork system 6 of the sunken wall protection well wall on the outside of the sump pit, and use a blowtorch to abut against the three inner sides of the concrete wall protection well wall 3 on the outside of the second pit The foam board is burnt out, and between the concrete wall 7 outside the sump pit and the concrete wall 3 outside the second pit, there is a gap 8 between the two caissons, so that when the subsequent inner caisson sinks, the gap between the two There will be no friction;

Step 8: Take out the soil below the concrete retaining wall 7 on the outside of the sump, so that the concrete retaining wall 7 on the outside of the sump sinks to the design elevation of the foundation pit of the sump by its own gravity At the place, excavate the soil in the concrete retaining wall 7 outside the sump to form the bottom 9 of the foundation pit of the sump;

The ninth step, in the gap 8 between the two caissons between the top surface of the concrete retaining wall well wall 7 outside the sump pit and the bottom end surface of the concrete retaining wall well wall 3 outside the second pit, set the cement paste pouring layer 10 , the gap 8 between the two caissons is closed, and the outer seepage of the two caissons is sealed;

The tenth step, on the bottom surface 4 of the foundation pit of the elevator shaft foundation, and on the bottom surface 9 of the foundation pit pit of the sump pit, respectively build a 200 mm thick sandstone cushion, and lay drainage pipes to facilitate the bottom of the two caissons. Water drains.

The height of the concrete retaining wall well wall 3 outside the second pit is 1.8 meters, and the height of the concrete retaining wall well wall 7 outside the sump pit is 1.4 meters; The concrete strength in 7 is the same, and the concrete strength in the cement slurry pouring layer 10 is one grade higher than the concrete strength in the concrete retaining wall shaft wall 3 outside the second pit; the final back cover, the two caissons, are used as supporting surrounding soil during construction The retaining wall of the body is buried in the soil as a permanent deep foundation after completion.

Claims (1)

1. A method for implementing elevator shaft and sump foundation retaining walls in easy-to-collapse soil, in which the elevator shaft foundation pit and sump pit foundation pit connected together are designed in the building body foundation pit (1), and the Characterized by the following steps: Step 1: On the bottom surface of the foundation pit of the building body (1), set out the construction outline (2) of the closed retaining wall outside the second pit of the foundation pit of the elevator shaft and the foundation pit of the sump pit; In the second step, on the construction outline (2) of the closed retaining wall outside the second pit, set up the cast-in-place concrete formwork system for the sinking retaining wall well wall outside the second pit, and pour concrete to form the concrete retaining wall well wall (3) outside the second pit; The third step is to dig out the soil below the outer concrete wall (3) of the second pit, so that the outer concrete wall (3) of the second pit will sink to the design elevation of the foundation pit of the elevator shaft by its own gravity position; dig out the soil in the outer concrete retaining wall (3) of the second pit that has sunk in place to form the bottom surface (4) of the foundation pit of the elevator shaft; Step 4: On the bottom surface of the foundation pit of the elevator shaft (4), set out the construction outline (5) of the closed retaining wall outside the foundation pit of the pre-set sump pit, and the construction outline of the outer retaining wall of the sump pit (5 ) is adjacent to the inner side of the outer concrete retaining wall (3) of the second pit, that is, the three sides of the construction outline (5) of the rectangular sump outer retaining wall are connected to the outer concrete retaining wall of the second pit ( 3) The three inner sides of the box are butted together; Step 5: Set up the cast-in-place concrete formwork system (6) on the construction outline (5) of the outer retaining wall of the sump pit, and set up the cast-in-place concrete formwork system (6) on the outer sinking retaining wall well wall of the sump pit. In the cast-in-place concrete formwork system (6), the outer formwork that abuts with the three inner sides of the outer concrete retaining wall (3) of the second pit uses a foam board; The sixth step is to pour concrete into the cast-in-situ concrete formwork system (6) for sinking the retaining wall well wall outside the sump pit to form a closed concrete retaining wall well wall (7) outside the sump pit; The seventh step is to remove the formwork in the cast-in-place concrete formwork system (6) of the sinking retaining wall well wall on the outside of the sump pit, and use a blowtorch to match the three inner surfaces of the concrete retaining wall well wall (3) on the outside of the second pit The foam boards abutted together are burnt out, and a gap (8) between the two caissons is formed between the concrete wall (7) outside the sump pit and the concrete wall (3) outside the second pit; Step 8: Take out the soil below the concrete retaining wall (7) on the outside of the sump, so that the concrete retaining wall (7) on the outside of the sump sinks to the foundation pit of the sump by its own gravity At the design elevation position of the sump pit, dig out the soil in the concrete retaining wall (7) outside the sump pit to form the bottom surface of the sump pit foundation pit (9); Step 9: In the gap between the two caissons (8) between the top surface of the concrete retaining wall (7) on the outside of the sinking sump and the bottom end of the concrete retaining wall (3) on the outside of the second pit, set The cement slurry pouring layer (10) seals the interval gap (8) between the two caissons; Step 10: On the bottom of the foundation pit of the elevator shaft (4) and the bottom of the foundation pit of the sump pit (9), respectively build a 200 mm thick sandstone cushion and arrange drainage pipes.