CN115233641A

CN115233641A - Ejection device for soil pressure box in underground cast-in-place structure and installation method of ejection device

Info

Publication number: CN115233641A
Application number: CN202110438428.4A
Authority: CN
Inventors: 曹永勇
Original assignee: Shanghai Municipal Engineering Construction Development Co ltd
Current assignee: Shanghai Municipal Engineering Construction Development Co ltd
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2022-10-25
Anticipated expiration: 2041-04-22
Also published as: CN115233641B

Abstract

The invention relates to a soil pressure cell ejection device in an underground cast-in-place structure and an installation method thereof, wherein the device comprises an outer sleeve, a base fixed at one end of the outer sleeve, an inner sleeve arranged in the outer sleeve, a spring arranged in the inner sleeve, and a soil pressure cell fixedly connected with one end of the inner sleeve, which is far away from the base; one end of the spring is fixed on the base, the other end of the spring is fixed on the inner-layer sleeve, and the soil pressure box and the inner-layer sleeve move relative to the outer-layer sleeve through the extension and contraction of the spring. The invention can improve the accuracy and the authenticity of the measured data of the soil pressure cell, improve the embedding efficiency, reduce the consumption of manpower and material resources, simplify the operation process, ensure that the operation is simpler and quicker, can be installed on the ground without going into an excavation well, realize the contact between the soil pressure cell and a rock-soil body by indirectly operating the control valve through the ground control stay wire, and judge whether the installation procedure is finished or not through the data fed back by the cable conductor.

Description

Ejection device for soil pressure box in underground cast-in-place structure and installation method of ejection device

Technical Field

The invention relates to the technical field of geotechnical engineering soil pressure detection, in particular to an ejection device for a soil pressure box in an underground cast-in-place structure and an installation method thereof.

Background

In recent years, as underground cast-in-place structural works have been increased in size and integrated, lateral soil pressure has greatly affected underground building structures. For the exposed soil pressure distribution situation, the lateral soil pressure measurement still takes the soil pressure cell as the main part, but the soil pressure cell is buried between the underground structure and the soil body, the operation space is narrow, and the phenomena of difficult fixation and positioning exist in the installation process. At present, the burying of a lateral soil pressure box in an underground cast-in-place structure mainly comprises a drilling method, a cloth hanging method, an air pressure method, a welding method, a binding method and the like.

The most common method for burying the current lateral soil pressure cell mainly comprises three methods: (1) The drilling method is that the earth behind the wall near the diaphragm wall is drilled, and then the calibrated earth pressure cell is put into the drilled hole and then filled with fine sand. The method needs secondary drilling, has higher construction cost, causes the surrounding soil body to generate soil arch effect by drilling, causes the internal stress of the surrounding soil body to be redistributed, and transmits the soil pressure acted after or on the arch to the arch springing and the surrounding soil body, thereby causing inaccurate test result. (2) The cloth hanging method is characterized in that a rated soil pressure cell is fixed on the cloth, and the upper and lower cell walls fix the soil pressure cell on the outer wall of the wall body by means of concrete pressure. The method has the defect that cement paste in concrete can easily permeate between the soil pressure box and the soil behind the wall in the process of pouring the concrete of the diaphragm wall, so that the soil pressure box is wrapped by the cement paste and is discarded. (3) The air pressure method is characterized in that a calibrated soil pressure box is fixed on an air pressure piece and then is arranged on a steel frame, the soil pressure box is put into a groove before concrete pouring, and air pressure is respectively applied to each instrument, so that the soil pressure box is fixed on the outer wall of a wall body. The method is complex to operate, and the jacking force provided by the pneumatic pressing piece is limited.

In addition, the soil pressure box embedded in the existing underground cast-in-place structure is directly hooped on the outer side of a reinforcement cage or welded on a cross beam. The two methods can well fix the soil pressure box on the cast-in-situ structure, but can not ensure that the soil pressure box is contacted with the rock-soil body, and even when the casting process is implemented, because the concrete and other fillers are extruded, the method has great deviation with the actual positioning, thereby being incapable of ensuring the accuracy and precision of the measuring result.

In summary, the conventional method for installing the soil pressure cell in the underground cast-in-place structure has the following problems and disadvantages: on one hand, the installation method is complicated, and time and labor are wasted; on the other hand, the measuring device is easy to damage and the accuracy of the instrument is low in the pouring process. These problems can directly or indirectly affect the monitoring of the soil pressure in an underground cast-in-place structure.

Three main influence factors for analyzing the reasons are as follows: (1) The problems of manpower and material resources are mainly solved by a drilling method, a cloth hanging method, an air pressure method, a welding method, a binding method and the like in the traditional installation. The drilling method needs to be carried out in a drilling hole and then installed, so that more human resources can be input, the precision of a measuring instrument cannot be guaranteed, and the deviation from an actual value is large. The cloth hanging method is characterized in that a steel structure hanging piece is prepared in advance, then the soil pressure box is arranged at different positions on the steel structure hanging piece, more materials are consumed by the middle method, meanwhile, the operation is complex, and sufficient jacking force cannot be guaranteed. The pneumatic method also does not provide sufficient thrust and is complicated to operate. (2) The measuring device is damaged, the soil pressure cell installed by the traditional method can be damaged in different degrees in the pouring process, the reinforcement cage can be driven to rotate along with the pouring process due to the force transmission effect, and the position of the soil pressure cell can be changed under the condition that enough pushing force cannot be guaranteed. Meanwhile, cement paste in the concrete easily permeates between the soil pressure box and the soil behind the wall, so that the soil pressure box is wrapped by the cement paste and is discarded. (3) The accuracy of the instrument is high, when the soil pressure cell is installed by using a traditional method, the drilling of the drilling method can cause the soil arch effect of the surrounding soil body, so that the internal stress of the surrounding soil body is redistributed, and the soil pressure acting after or on the arch is transmitted to the arch springing and the surrounding soil body, so that the test result is inaccurate. The cloth hanging method and the air pressure method cannot guarantee enough jacking force, cannot guarantee complete direct contact with a rock-soil body interface in the pouring process, and the binding method and the welding method also have the same phenomenon, so that the difference between the value measured by an instrument and the actual value is larger under the conditions.

Therefore, how to provide the ejection device for the soil pressure cell in the underground cast-in-place structure and the installation method thereof, which are used for solving the technical problems of complicated steps, time and labor waste, low instrument accuracy and the like in the traditional method for installing the soil pressure cell in the underground cast-in-place structure, and have important significance for the application of the ejection device.

Disclosure of Invention

In view of this, the present application provides an earth pressure cell ejection device in an underground cast-in-place structure and an installation method thereof, so as to solve various problems existing in the traditional method that an underground cast-in-place structure is buried laterally with an earth pressure cell, improve accuracy and authenticity of measurement data of the earth pressure cell, improve burying efficiency, and reduce consumption of manpower and material resources.

In order to achieve the above object, the present application provides the following technical solutions.

A soil pressure box ejection device in an underground cast-in-place structure comprises an outer sleeve, a base fixed at one end of the outer sleeve, an inner sleeve arranged in the outer sleeve, a spring arranged in the inner sleeve, and a soil pressure box fixedly connected with one end, far away from the base, of the inner sleeve;

one end of the spring is fixed on the base, the other end of the spring is fixed on the inner-layer sleeve, and the soil pressure box and the inner-layer sleeve move relative to the outer-layer sleeve through the extension and contraction of the spring.

Preferably, the device further comprises a control valve, the control valve is connected with a pull wire which plays a role of a control switch, and the control valve is used for fixing the spring in the inner sleeve and controlling the extension and the release of the spring.

Preferably, the soil pressure cell is connected with the cable conductor that is used for connecting measuring equipment, soil pressure cell one end is provided with positioning nut, be provided with the set screw corresponding with positioning nut on the inlayer sleeve, realize the fixed connection of inlayer sleeve and soil pressure cell through positioning nut and set screw.

Preferably, the one end that the inlayer sleeve is being close to the base is provided with first stopper, the one end that the base is being kept away from to outer sleeve is provided with limit baffle, first stopper and limit baffle cooperate for prevent the inlayer sleeve breaks away from outer sleeve.

Preferably, a middle sleeve is arranged between the inner sleeve and the outer sleeve, and the movement of the inner sleeve relative to the middle sleeve and the movement of the middle sleeve relative to the outer sleeve can be realized through the extension and contraction of the spring.

Preferably, a fixed fixture block is arranged at one end, far away from the base, of the middle-layer sleeve, the fixed fixture block is matched with the first limiting block, and when the inner-layer sleeve moves to an extreme position relative to the middle-layer sleeve, the fixed fixture block can drive the middle-layer sleeve to continue to move;

the second limiting block is arranged at one end, close to the base, of the middle-layer sleeve and matched with the limiting baffle plate to prevent the middle-layer sleeve from being separated from the outer-layer sleeve.

Preferably, the lengths of the outer sleeve, the middle sleeve and the inner sleeve are all 300-400 mm, and the diameter of the outer sleeve is 80-100 mm.

Preferably, the thickness of the outer sleeve, the thickness of the middle sleeve and the thickness of the inner sleeve are all 1-2 mm, the thickness of the inner sleeve is smaller than that of the middle sleeve, and the thickness of the middle sleeve is smaller than that of the outer sleeve.

Preferably, the stiffness coefficient of the spring is 40-60 KN/m and can be selected according to the hardness degree of the rock-soil body.

The installation method of the soil pressure box ejection device in the underground cast-in-place structure comprises the following steps:

101. firstly fixing a soil pressure cell which is calibrated in advance on an inner layer sleeve, and then fixing a base on a reinforcement cage in a binding or electric welding mode;

102. after the fixing, loosening the pull wire and the cable, and pulling the pull wire and the cable to the position of a pouring opening along the reinforcement cage;

103. the control valve is opened through the pull wire, so that the inner-layer sleeve extends under the action of the elastic force of the spring, when the bottom of the soil pressure box touches the rock-soil body, the extension speed of the inner-layer sleeve and/or the middle-layer sleeve is reduced under the action of the rock-soil body, and meanwhile, the soil pressure box continues to extrude the rock-soil body until the stress at the two ends reaches balance;

104. connecting a cable to the measuring equipment, and starting to pour concrete when the measured soil pressure data tend to be stable, wherein the speed of the pouring process is reasonably controlled in consideration of the existence of the measuring equipment, and the measured soil pressure data are recorded.

The beneficial technical effects obtained by the invention are as follows:

1) The invention solves various problems existing in the traditional method for burying the lateral soil pressure cell of the underground cast-in-place structure, such as insufficient jacking force, improves the accuracy and the authenticity of the measured data of the soil pressure cell, improves the burying efficiency, reduces the consumption of manpower and material resources, simplifies the operation process, ensures that the operation is simpler and quicker, can be installed on the ground without going into an excavated well, realizes the contact between the soil pressure cell and a rock-soil body by indirectly operating a control valve through a ground control stay wire, and judges whether the installation procedure is completed or not through the data fed back by a cable.

2) The invention is more economical and practical, consists of three groups of sleeves and a spring system, has relatively low cost, does not need excessive manpower and material resources compared with methods such as a drilling method, a cloth hanging method, an air pressure method and the like, greatly reduces the space, is more convenient to carry, ensures the requirement of the size through a pull rod principle, and simultaneously provides enough jacking force.

3) The invention can provide enough top thrust, can adjust and control the top thrust by selecting the stiffness coefficient K of the spring, has different top thrust provided by the stiffness coefficients (stiffness coefficient/elastic coefficient) of different springs, can obtain the distance between the size of a cast-in-place structure and an excavation surface according to the actual construction working condition, and calculates the top thrust by f = kx (Hooke's law).

4) The invention can ensure the accuracy and authenticity of the transmitted data, further judge by measuring the data fed back by the soil pressure cell in the installation process and the pouring process in real time, and simultaneously, the device is not limited by the embedding depth and can meet the embedding depth requirement of the structure.

The foregoing description is only an overview of the technical solutions of the present application, so that the technical means of the present application can be clearly understood, and the present application can be implemented according to the content of the description, and the foregoing and other objects, features, and advantages of the present application can be more clearly understood.

The above and other objects, advantages and features of the present application will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, as illustrated in the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following descriptions are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

FIG. 1 is a schematic structural diagram of an earth pressure cell ejection device in an underground cast-in-place structure according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram of an embodiment of the present disclosure after initial extension of an earth pressure cell ejector in an underground cast-in-place structure;

fig. 3 is a schematic structural view of an earth pressure cell ejection device in an underground cast-in-place structure after ultimate extension according to an embodiment of the disclosure.

In the drawings above: 100. an outer sleeve; 110. a limit baffle; 200. an inner sleeve; 210. a first stopper; 220. a set screw; 300. a middle sleeve; 310. fixing the fixture block; 320. a second limiting block; 400. a spring; 500. a soil pressure cell; 510. a cable wire; 520. positioning a nut; 600. a base; 700. a control valve; 710. and pulling a wire.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. In the following description, specific details such as specific configurations and components are provided only to help the embodiments of the present application be fully understood. Accordingly, it will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, descriptions of well-known functions and constructions are omitted in the embodiments for clarity and conciseness.

It should be appreciated that reference throughout this specification to "one embodiment" or "the present embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrase "one embodiment" or "the present embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Further, the present application may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: the three cases of A alone, B alone and A and B together exist, and the term "/and" in this document describes another associated object relationship, which means that two relationships may exist, for example, A/and B, which may mean: a alone, and both a and B alone, and further, the character "/" in this document generally means that the former and latter associated objects are in an "or" relationship.

The term "at least one" herein is merely an association relationship describing an associated object, and means that there may be three relationships, for example, at least one of a and B, may mean: a exists alone, A and B exist simultaneously, and B exists alone.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion.

Example 1

As shown in fig. 1, the soil pressure cell ejecting device in the underground cast-in-place structure comprises an outer sleeve 100, a base 600 fixed at one end of the outer sleeve 100, an inner sleeve 200 arranged inside the outer sleeve 100, a spring 400 arranged inside the inner sleeve 200, and a soil pressure cell 500 fixedly connected with one end of the inner sleeve 200 far away from the base 600.

One end of the spring 400 is fixed on the base 600, the other end of the spring 400 is fixed on the inner sleeve 200, and the soil pressure cell 500 and the inner sleeve 200 move relative to the outer sleeve 100 through the extension and contraction of the spring 400.

Further, the device further comprises a control valve 700, wherein a pull wire 710 functioning as a control switch is connected to the control valve 700, and the control valve 700 is used for fixing the spring 400 in the inner sleeve 200 and controlling the extension and the retraction of the spring 400.

Soil pressure cell 500 is connected with and is used for connecting measuring equipment's cable conductor 510, soil pressure cell 500 one end is provided with set nut 520, be provided with on the inlayer sleeve 200 with the corresponding set screw 220 of set nut 520, realize inlayer sleeve 200 and soil pressure cell 500's fixed connection through set nut 520 and set screw 220.

Further, as shown in fig. 2, a first limit block 210 is disposed at one end of the inner sleeve 200 close to the base 600, a limit baffle 110 is disposed at one end of the outer sleeve 100 far from the base 600, and the first limit block 210 and the limit baffle 110 are matched to prevent the inner sleeve 200 from separating from the outer sleeve 100.

In one embodiment, as shown in fig. 3, a middle sleeve 300 is disposed between the inner sleeve 200 and the outer sleeve 100, and the movement of the inner sleeve 200 relative to the middle sleeve 300 and the movement of the middle sleeve 300 relative to the outer sleeve 100 can be realized by the extension and contraction of the spring 400.

The middle sleeve 300 is provided with a fixed fixture 310 at one end away from the base 600, the fixed fixture 310 is matched with the first limiting block 210, and when the inner sleeve 200 moves to an extreme position relative to the middle sleeve 300, the middle sleeve 300 can be driven to move continuously.

The middle sleeve 300 is provided with a second stopper 320 at one end close to the base 600, and the second stopper 320 is matched with the stopper 110 to prevent the middle sleeve 300 from separating from the outer sleeve 100.

The lengths of the outer sleeve 100, the middle sleeve 300 and the inner sleeve 200 are all 300-400 mm, the lengths of the three are equal, and the diameter of the outer sleeve 100 is 80-100 mm.

The thicknesses of the outer sleeve 100, the middle sleeve 300 and the inner sleeve 200 are all 1-2 mm, the thickness of the inner sleeve 200 is smaller than that of the middle sleeve 300, and the thickness of the middle sleeve 300 is smaller than that of the outer sleeve 100.

The stiffness coefficient of the spring 400 is 40-60 KN/m, and can be selected according to the hardness degree of rock-soil bodies.

Fig. 2 and 3 are views illustrating the extension process of the entire apparatus after the control valve 700 is pulled open by a pulling line 710, in which fig. 2 illustrates a state in which the apparatus is in a state in which the inner sleeve 200 reaches a maximum value, and fig. 3 illustrates a state in which the entire apparatus reaches a maximum value, during which the extension of the inner sleeve 200 and the middle sleeve 300 is provided by the elastic force stored in the spring 400, and the specific positions reached by the inner sleeve 200 and the middle sleeve 300 are determined according to the cast-in-place environment, and the extension is stopped when they meet the rock mass.

Example 2

Based on the embodiment 1, the installation method of the soil pressure box ejection device in the underground cast-in-place structure comprises the following steps:

101. firstly, a soil pressure cell 500 which is preset is fixed on the inner sleeve 200, and then the base 600 is fixed on the reinforcement cage by binding or electric welding.

Specifically, the soil pressure cell 500 is fixedly connected with the inner sleeve 200 through the positioning nut 520 and the positioning screw 220, and in order to prevent the displacement of the whole device in the pouring process, one end of the soil pressure cell 500 fixedly connected with the inner sleeve 200 is reinforced by adopting a binding or electric welding mode.

102. After the fixing is finished, the stay wire 710 and the cable 510 are loosened and pulled to the pouring opening position along the reinforcement cage.

103. The control valve 700 is opened by the pull wire 710 so that the inner sleeve 200 is extended by the elastic force of the spring 400, and when the bottom of the soil pressure cell 500 touches the rock-soil mass, the extension speed of the inner sleeve 200 and/or the middle sleeve 300 is decreased by the force of the rock-soil mass, and simultaneously the soil pressure cell 500 continues to press the rock-soil mass until the forces at both ends are balanced.

104. Cable 510 is connected to a measuring device and concrete is poured when the measured soil pressure data tends to be stable, taking into account the presence of the measuring device, the pouring process should be reasonably speed controlled and the measured soil pressure data recorded.

It should be noted that the reinforcement cage is an application part of the present application, and belongs to the prior art to those skilled in the art.

The spring 400 in the soil pressure box ejection device in the underground cast-in-place structure conforms to Hooke's law which points out that: within the elastic limit, the deformation of an object is proportional to the external force causing the deformation, and the expression hooke's law is f = kx, where k is a constant, which is the elastic coefficient of the object. Meanwhile, the principle of the telescopic rod is utilized, the telescopic rod is a telescopic hollow cylindrical rod which is formed by rolling a metal strip, and the telescopic rod is characterized in that the metal strip is pre-shaped into an elastic curled layer which has a memory function and is smaller than the outer diameter of the rod body, so that the telescopic rod has a self-tightening function, and the curled layer always has elastic potential energy for applying pressure to the telescopic rod. The device adopts the telescopic link principle, combines spring 400 system again, can satisfy ejecting device suitable size, provides sufficient jacking force simultaneously.

The soil pressure cell ejection device in the underground cast-in-place structure can provide enough ejection force, the ejection force can be controlled by selecting the stiffness coefficient K of the spring 400, the stiffness coefficients (stiffness coefficient/elastic coefficient) of different springs 400 are different, the distance between the size of the cast-in-place structure and an excavation surface can be obtained according to actual construction working conditions, and the ejection force is calculated through f = kx (hooke's law). The device has the advantages that the space is greatly reduced, the carrying is more convenient, the requirement on the size is guaranteed through the pull rod principle, and meanwhile, the sufficient jacking force is provided.

The above description is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the present invention, and various modifications and changes may be made by those skilled in the art. Variations, modifications, substitutions, integrations and parameter changes of the embodiments may be made by the conventional substitutes or the same functions may be performed within the spirit and principle of the invention without departing from the principle and spirit of the invention.

Claims

1. The ejection device for the soil pressure cell in the underground cast-in-place structure is characterized by comprising an outer layer sleeve (100), a base (600) fixed at one end of the outer layer sleeve (100), an inner layer sleeve (200) arranged in the outer layer sleeve (100), a spring (400) arranged in the inner layer sleeve (200), and a soil pressure cell (500) fixedly connected with one end, far away from the base (600), of the inner layer sleeve (200);

one end of the spring (400) is fixed on the base (600), the other end of the spring is fixed on the inner-layer sleeve (200), and the soil pressure box (500) and the inner-layer sleeve (200) move relative to the outer-layer sleeve (100) through the extension and retraction of the spring (400).

2. An ejection apparatus for a soil pressure cell in an underground cast-in-place structure according to claim 1, further comprising a control valve (700), wherein the control valve (700) is connected with a pull wire (710) functioning as a control switch, and the control valve (700) is used for fixing the spring (400) in the inner sleeve (200) and controlling the extension and the retraction of the spring (400).

3. The soil pressure cell ejection device in the underground cast-in-place structure and the installation method thereof according to claim 1, wherein the soil pressure cell (500) is connected with a cable (510) for connecting a measuring device, one end of the soil pressure cell (500) is provided with a positioning nut (520), the inner sleeve (200) is provided with a positioning screw (220) corresponding to the positioning nut (520), and the inner sleeve (200) is fixedly connected with the soil pressure cell (500) through the positioning nut (520) and the positioning screw (220).

4. An ejection device for a soil pressure cell in an underground cast-in-place structure according to claim 1, wherein the inner sleeve (200) is provided with a first limit block (210) at one end close to the base (600), the outer sleeve (100) is provided with a limit baffle (110) at one end far away from the base (600), and the first limit block (210) and the limit baffle (110) are matched for preventing the inner sleeve (200) from separating from the outer sleeve (100).

5. The soil pressure cell ejection device in the underground cast-in-place structure according to claim 4, wherein a middle sleeve (300) is arranged between the inner sleeve (200) and the outer sleeve (100), and the movement of the inner sleeve (200) relative to the middle sleeve (300) and the movement of the middle sleeve (300) relative to the outer sleeve (100) can be realized through the extension and contraction of the spring (400).

6. The soil pressure cell ejection device in the underground cast-in-place structure as claimed in claim 5, wherein the middle sleeve (300) is provided with a fixed block (310) at one end far away from the base (600), the fixed block (310) is matched with the first limit block (210), and when the inner sleeve (200) moves to a limit position relative to the middle sleeve (300), the fixed block can drive the middle sleeve (300) to move continuously;

one end of the middle layer sleeve (300) close to the base (600) is provided with a second limiting block (320), and the second limiting block (320) is matched with the limiting baffle (110) and used for preventing the middle layer sleeve (300) from being separated from the outer layer sleeve (100).

7. The soil pressure cell ejection device in the underground cast-in-place structure of claim 5, wherein the length of the outer sleeve (100), the length of the middle sleeve (300) and the length of the inner sleeve (200) are all 300-400 mm, and the diameter of the outer sleeve (100) is 80-100 mm.

8. The soil pressure cell ejection device in the underground cast-in-place structure of claim 5, wherein the thickness of the outer sleeve (100), the middle sleeve (300) and the inner sleeve (200) is 1-2 mm, the thickness of the inner sleeve (200) is less than that of the middle sleeve (300), and the thickness of the middle sleeve (300) is less than that of the outer sleeve (100).

9. The ejection device for the soil pressure cell in the underground cast-in-place structure according to claim 1, wherein the stiffness coefficient of the spring (400) is 40-60 KN/m, and can be selected according to the hardness degree of the rock-soil body.

10. The method for installing an earth pressure cell ejector in an underground cast-in-place structure according to claim 1, comprising the steps of:

101. firstly fixing a soil pressure cell which is preset on an inner sleeve (200), and then fixing a base (600) on a reinforcement cage in a binding or electric welding manner;

102. after the fixing, the pull wire (710) and the cable (510) are loosened, and the pull wire is pulled to the position of a pouring opening along the reinforcement cage;

103. the control valve (700) is opened through the pull wire (710), so that the inner sleeve (200) extends under the elastic force of the spring (400), when the bottom of the soil pressure box (500) touches the rock-soil body, the extension speed of the inner sleeve (200) and/or the middle sleeve (300) under the acting force of the rock-soil body is reduced, and meanwhile, the soil pressure box (500) continues to extrude the rock-soil body until the stress at the two ends reaches balance;

104. the cable (510) is connected to a measuring device, and when the measured soil pressure data tend to be stable, the concrete is poured, and the pouring process is reasonably controlled in speed by considering the existence of the measuring device, and the measured soil pressure data are recorded.