CN107100650B - A rectangular steel tube curtain foot connection structure and its construction method - Google Patents

Abstract

The invention provides a rectangular steel pipe curtain foot connecting structure and a construction method thereof, wherein the rectangular steel pipe curtain foot connecting structure comprises an L-shaped foundation arranged in a pilot tunnel, a vertical steel pipe arranged outside the pilot tunnel and two rows of vertical bolts used for connecting the vertical steel pipe and the L-shaped foundation, two rows of bolt holes corresponding to the vertical bolts are formed in one surface of the vertical steel pipe, facing the L-shaped foundation, of the vertical steel pipe, one end of each vertical bolt penetrates through the bolt hole in the vertical steel pipe, and the other end of each vertical bolt is connected with the L-shaped foundation through an embedded bar. The invention has simple structure, is convenient for construction, reduces the jacking quantity of the vertical pipe curtains, greatly reduces the construction period, and can be suitable for the basic forms of various pipe curtain construction methods; the L-shaped foundation form can be perfectly matched with the later-stage main body structure, so that the space utilization rate is increased, the construction is convenient, and the economic benefit is improved.

Description

A rectangular steel tube curtain foot connection structure and its construction method

Technical field

The invention relates to a subway underground excavation station using a tube curtain structure as a supporting structure, and mainly relates to the structure of the foot foundation of the tube curtain structure and the connection method between the tube curtain structure and the foundation.

Background technique

In recent years, urban underground engineering construction has entered a golden period. As technology advances, the support concepts and methods used for excavation are gradually changing. Among them, excavation under the form of pipe curtain support will have less impact on the surface and surrounding environment, and the pipe curtain construction method can block water to a certain extent. Therefore, many projects under construction or already built in my country are constructed in the form of pipe curtain support. The general form of tube curtain structure is a semi-enclosed arch structure. This structure has better mechanical performance, but its space utilization is small. Therefore, a flat-top rectangular tube curtain structure has emerged. In order to ensure that this kind of pipe curtain structure does not sink as a whole when the soil beneath the pipe curtain is excavated, it is necessary to reinforce the feet of the pipe curtain structure. Multiple steel pipes are often connected side by side to increase the strength of the feet of the pipe curtain structure. Bearing capacity, see Figure 1. However, this reinforcement method requires increasing the number of pipe jacking and prolonging the construction period. In addition, during the pipe jacking construction process, the jacking accuracy is difficult to control. If the deviation is large, it will be difficult to connect adjacent steel pipes, which will reduce the strength of the ends of the pipe curtain. The reinforcement effect will cause the overall sinking of the pipe curtain structure, thereby affecting the support effect of the pipe curtain structure.

Contents of the invention

The invention provides a connection structure and construction method that is easy to construct and can effectively reinforce the feet of the tube curtain structure. The reinforcement effect is more significant. It is combined with the later construction of the side walls and bottom plates of the station to optimize the construction steps.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

A rectangular steel pipe curtain foot connection structure, including an L-shaped foundation placed in a guide hole, a vertical steel pipe located outside the guide hole, and two rows of vertical bolts for connecting the vertical steel pipe and the L-shaped foundation, said There are two rows of bolt holes corresponding to the vertical bolts on the side of the vertical steel pipe facing the L-shaped foundation. One end of the vertical bolts passes through the bolt holes on the vertical steel pipe, and the other end is connected to the L-shaped foundation through embedded steel bars. .

Small-diameter steel pipes are vertically arranged in the area between the vertical steel pipes and the L-shaped foundation, and the small-diameter steel pipes are used to pass through vertical bolts.

The vertical bolts and embedded steel bars are welded in the small diameter steel pipe.

The invention also provides a construction method for a rectangular steel pipe curtain foot connection structure, which includes the following steps:

1) First, use the step method to construct the guide tunnel under the pipe curtain, and perform support while excavation until it is penetrated along the axial direction of the pipe curtain. During the construction of the guide tunnel, according to the spacing of the bolt holes of the vertical steel pipes, at the beginning of the underground excavation Small diameter steel pipes are embedded in the branch;

2) Next, construct the L-shaped foundation. When the steel frame starts to be tied, pre-embedded steel bars are set on the top. During pre-embedding, random adjustments are made according to the hole positions of the small-diameter steel pipes embedded in the guide holes to ensure that they are on the same center line. Above, after the steel frame overlap is completed, concrete is poured into the formwork;

3) Jack up the vertical steel pipe;

4) After the pipe jacking is completed, pass the vertical bolts through the bolt holes to ensure that the small diameter steel pipe can be welded to the embedded steel bars of the L-shaped foundation without removing the guide tunnel support;

5) After the vertical bolts and embedded steel bars are welded, concrete is poured as a whole for the joint formwork, and the overall pipe curtain structure and foot reinforcement are completed.

It can be seen from the above technical solutions that the present invention has a simple structure, is easy to construct, reduces the number of vertical pipe curtain jackings, greatly reduces the construction period, and can be applied to the foundation forms of various pipe curtain construction methods; the L-shaped foundation form can be used with The main structure in the later stage fits perfectly, which increases space utilization, facilitates construction, and improves economic benefits.

Description of the drawings

Figure 1 is a schematic diagram of the connection structure of the rectangular steel pipe curtain foot part of the present invention;

Figure 2 is a cross-sectional view of a station using the rectangular tube curtain foot connection structure of the present invention;

Figure 3 is a top view of the vertical steel pipe in the present invention.

Detailed ways

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 2, the rectangular steel tube curtain foot connection structure 10 is part of the tube curtain support, used to reinforce the foot of the tube curtain structure, and perfectly fits the later main structure 20, increasing space utilization. Convenient for construction.

As shown in Figures 1 and 3, the rectangular steel tube curtain foot connection structure 10 includes an L-shaped foundation 30 and a vertical steel pipe 40. The L-shaped foundation is placed inside the underground guide tunnel 70, and the vertical steel pipe is placed outside the guide tunnel, where Two rows of bolt holes 41 are provided on the side of the vertical steel pipe facing the guide hole. The vertical steel pipe and the L-shaped foundation are fixedly connected through vertical bolts 50.

One end of the vertical bolt 50 passes through the bolt hole 41 on the vertical steel pipe, and the other end is connected to the L-shaped foundation 30 through the embedded steel bar 31. A small-diameter steel pipe 60 is vertically arranged in the area between the vertical steel pipe and the L-shaped foundation. The small-diameter steel pipe is used to pass through the vertical bolts, so that the vertical bolts and the embedded steel bars are welded in the small-diameter steel pipe.

The specific method for using the rectangular steel tube curtain foot connection structure in the construction of the tube curtain structure according to the present invention is as follows:

1. First, use the step method to construct the guide tunnel 70 below the pipe curtain, and perform support while excavation until it is penetrated along the axial direction of the pipe curtain. During the construction of the guide tunnel, a φ45@150 small-diameter steel pipe 60 was pre-buried in the first branch of the underground excavation according to the spacing between the bolt holes of the vertical steel pipes. The two ends of the pre-buried pipe were sealed with plastic tape to prevent concrete from entering. The grid is fixed to prevent the small-diameter steel pipe from shifting during concrete spraying.

2. When constructing the L-shaped foundation, pre-embedded steel bars 31 should be set on the top of the steel frame when starting to be tied. The pre-embedded length should meet 35d, and the exposed length should be greater than 32d. When pre-embedded, the holes of the small-diameter steel pipes in the guide tunnel should be dug underground. Randomly adjust the position to ensure that the two are on the same center line for subsequent connection. After the steel frame overlap is completed, the formwork is poured with concrete.

3. During the steel pipe jacking process, it is crucial to control the accuracy of the vertical steel pipes connected in the underground guide tunnel. It not only affects the direction of the upper pipe jacking, but also affects the connection with the L-shaped foundation. During construction, continuous measurements should be taken, deviations should be corrected in time, and the upper and lower holes of the vertical steel pipe should be level, so that the bolt holes are connected with the upper and lower connecting holes of the small diameter steel pipe.

4. After the pipe jacking is completed, pass the vertical bolts 50 through the bolt holes 41 to ensure that the small-diameter steel pipes 60 and the embedded steel bars of the L-shaped foundation can be pre-buried through underground excavation without removing the support of the guide tunnel. 31 Welding, the welding length is not less than 10d.

5. After the vertical bolts and embedded steel bars are welded, quality inspection is carried out. After passing the inspection, concrete is poured as a whole for the joint formwork, and the overall pipe curtain structure and foot reinforcement construction are completed.

The above-described embodiments are only descriptions of preferred embodiments of the present invention and do not limit the scope of the present invention. Various modifications to the technical solutions of the present invention may be made by those of ordinary skill in the art without departing from the design spirit of the present invention. and improvements shall fall within the protection scope determined by the claims of the present invention.

Claims (3)

1. A construction method of a rectangular steel pipe curtain foot connecting structure is characterized in that,

the rectangular steel pipe curtain foot connecting structure comprises an L-shaped foundation arranged in a pilot tunnel, a vertical steel pipe arranged outside the pilot tunnel and two rows of vertical bolts used for connecting the vertical steel pipe and the L-shaped foundation, wherein two rows of bolt holes corresponding to the vertical bolts are formed in one face of the vertical steel pipe, facing the L-shaped foundation, of each vertical steel pipe, one end of each vertical bolt penetrates through the bolt hole in the vertical steel pipe, and the other end of each vertical bolt is connected with the L-shaped foundation through an embedded steel bar; a small-diameter steel pipe is vertically arranged in the area between the vertical steel pipe and the L-shaped foundation and is used for penetrating through a vertical bolt, and the vertical bolt and the embedded steel bar are welded in the small-diameter steel pipe;

the construction method comprises the following steps:

1) Firstly, constructing a pilot tunnel below a pipe curtain by adopting a step method, excavating while supporting until the pilot tunnel is penetrated along the axial direction of the pipe curtain, and pre-burying small-diameter steel pipes in a pre-excavated primary support according to the intervals of bolt holes of vertical steel pipes during pilot tunnel construction;

2) Then constructing an L-shaped foundation, arranging embedded bars at the top of the L-shaped foundation when the steel skeleton starts to be bound, randomly adjusting the embedded bars according to the hole positions of the small-diameter steel pipes embedded in the pilot tunnel when the embedded bars are embedded, ensuring that the embedded bars and the steel skeleton are on the same central line, and supporting a mold to pour concrete after the steel skeleton is overlapped;

3) Jacking a vertical steel pipe;

4) After the jacking pipe is completed, the vertical bolts penetrate downwards from the bolt holes, so that the welding between the small-diameter steel pipes and embedded bars of the L-shaped foundation can be ensured under the condition that the pilot tunnel support is not required to be broken;

5) After the welding of the vertical bolts and the embedded bars is finished, the formwork is supported at the joint, the concrete is integrally poured, and the whole pipe curtain structure and the foot reinforcement construction are finished.

2. The construction method according to claim 1, wherein in step 1), both ends of the small-diameter steel pipe before embedding are plugged with plastic tapes to prevent concrete from entering, and are fixed with a grid.

3. The construction method according to claim 1, wherein the measurement is performed continuously and the correction is performed in time during the jacking of the vertical steel pipe, so that the level of the upper and lower hole positions of the vertical steel pipe is ensured, and the bolt holes of the vertical steel pipe are communicated with the upper and lower connecting holes of the small-diameter steel pipe.