CN114809122A

CN114809122A - Inner supporting device capable of accurately applying prestress in foundation pit model test

Info

Publication number: CN114809122A
Application number: CN202210326310.7A
Authority: CN
Inventors: 周强; 裴昊田; 衣凡; 程雪松; 郭景琢; 马庆伟; 李钟顺
Original assignee: Tianjin University; China Construction Infrastructure Co Ltd
Current assignee: Tianjin University; China Construction Infrastructure Co Ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2022-07-29

Abstract

The invention discloses an inner support device capable of accurately applying prestress in a foundation pit model test, which comprises an inner support model main body made of PVC pipes, wherein a pressure sensor is arranged in the middle of the inner support model main body, bolts which are in threaded connection with the inner support model main body are arranged at two ends of the inner support model main body, when the inner support model main body is used, the bolts are hinged with a ground connection wall model device, the support length of the inner support model is adjusted by screwing the bolts, the prestress is applied by adjusting the support length of the inner support model, and the magnitude of the applied prestress is measured by the pressure sensor. According to the invention, an accurate axial pressure value of the inner support model can be obtained through the pressure sensor, the tedious operation of measuring the inner support pressure by adopting a strain gauge in the traditional test method is avoided, the test device is more accurate, concise, reliable and efficient, the accurate application of prestress is realized through simple operation, and the accurate axial force value of the support can be obtained.

Description

Inner supporting device capable of accurately applying prestress in foundation pit model test

Technical Field

The invention belongs to the field of foundation pit engineering model tests, and particularly relates to an inner supporting device capable of accurately applying prestress in a foundation pit model test.

Background

In recent years, foundation pit engineering at home and abroad is rapidly developed, an underground diaphragm wall and inner support supporting system is widely applied to actual engineering as a common foundation pit supporting form, meanwhile, related theoretical research work is continuously developed, and a model test is widely applied to theoretical research of the foundation pit engineering as a common research mode.

The inner support is one of the most main structural members of the ground connecting wall and inner support supporting system, and two ends of the inner support are hinged to the ground connecting walls on two sides in the engineering and are mainly stressed by the axle center pressure. The inner support model member adopted by the existing model test is a common PVC pipe, two ends of the inner support model member are hinged and fixed with the ground connecting wall through bolts, and the axial force of the support is measured through a strain gauge. Traditional interior strutting arrangement not only can not adjust the prestressing force value size of interior support on the one hand, and on the other hand pastes the foil gage comparatively complicacy, and the foil gage is fragile to acquire data comparatively loaded down with trivial details, when the axle power that needs simultaneous measurement multichannel to support, the operation is more complicated, because uncontrollable environmental factor, the data measurement inaccuracy scheduling problem that leads to such as circuit fault factor also is more serious for development of relevant scientific research work has met certain resistance.

Disclosure of Invention

The invention provides an inner supporting device capable of accurately applying prestress in a foundation pit model test for solving the technical problems in the known technology, which can realize accurate application of prestress through simple operation and obtain an accurate numerical value of the supporting shaft force.

The technical scheme adopted by the invention for solving the technical problems in the prior art is as follows: the inner support device comprises an inner support model main body made of PVC pipes, wherein a pressure sensor is arranged in the middle of the inner support model main body, bolts which are in threaded connection with the inner support model main body are arranged at two ends of the inner support model main body, the bolts are hinged with a ground connection wall model device during use, the support length of the inner support model is adjusted by screwing the bolts, prestress is applied by adjusting the support length of the inner support model, and the prestress is applied by measuring the pressure sensor.

The pressure sensor is connected with a computer to measure the supporting axial force in real time.

The top of the bolt is provided with a pin shaft hole extending along the length direction of the bolt, and a pin shaft matched with the pin shaft hole is arranged on the diaphragm wall model device.

The invention has the advantages and positive effects that: through adopting in supporting the model main part with adding the structure of establishing pressure sensor, can obtain accurate interior support model axial pressure numerical value through pressure sensor on the one hand, avoided in the traditional test method, adopt the foil gage to measure the loaded down with trivial details operation of interior support pressure, make testing arrangement more accurate, succinct, reliable, high-efficient. On the other hand, the length of the inner support model is changed by adopting a mode of controlling the depth of the screwed bolt, and the reading of the pressure sensor is combined, so that the prestress applied to the inner support model is accurately controlled, and convenience is provided for a foundation pit engineering model test related to prestress support. In summary, the present invention realizes accurate application of prestress by simple operation, and can obtain accurate numerical value of support shaft force.

Drawings

FIG. 1 is a schematic view of the structure of the present invention;

FIG. 2 is a schematic structural diagram of an application of the present invention;

fig. 3 is a schematic structural view of the installation of the present invention.

In the figure: 1. supporting the model body inside; 2. a pressure sensor; 3. a bolt; 4. a data line; 5. a diaphragm wall model device; 6. and (3) a hinge structure.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

referring to fig. 1 to 3, an inner support device capable of accurately applying prestress in a foundation pit model test includes an inner support model main body 1 made of PVC pipe, a pressure sensor 2 is disposed in the middle of the inner support model main body 1, bolts 3 connected with the inner support model main body 1 through threads are disposed at two ends of the inner support model main body 1, when in use, the bolts 3 are connected with a ground connection wall model device 5 through a hinge structure 6, the support length of the inner support model is adjusted by screwing the bolts 3, prestress is applied by adjusting the support length of the inner support model, and the magnitude of the prestress applied is measured by the pressure sensor 2.

Threaded holes are formed in two ends of the inner support model body 1, bolts 3 are screwed into the threaded holes, and after the two ends of the inner support model are connected to the ground wall model device 5, the length of the bolts 3 screwed into the inner support model body 1 at one end or two ends is adjusted, so that the length of the inner support model is controlled, and the prestress applied to the inner support model is controlled. When prestress is applied, the bolt 3 in the inner support model body 1 is screwed out to be tightly propped against the ground connecting wall, and when the numerical value measured by the pressure sensor 2 reaches the numerical value of the prestress to be applied, the screwing depth of the bolt 3 is kept fixed. The pressure sensor 2 can accurately measure the axial pressure applied to the inner support device, namely the prestress applied by the inner support model. In the test process, the pressure sensor 2 can continuously monitor the magnitude of the axial force borne by the inner support model.

In the embodiment, the pressure sensor 2 is connected with a computer through a data line 4, and the supporting shaft force is measured in real time. The top of the bolt 3 is provided with a pin shaft hole extending along the length direction of the bolt, and a pin shaft matched with the pin shaft hole is arranged on the diaphragm wall model device and used for implementing the hinging of the bolt 3 and the diaphragm wall model device 5.

Referring to FIG. 3, the following is illustrated in more detail:

1) the inner support means is first connected to the diaphragm wall formwork means 5.

2) The depth of the bolt 3 at one side screwed into the inner support model body 1 is fixed, as shown by the first in FIG. 3; the bolt 3 at the other side is screwed out to tightly push against the wall model device 5, as shown in the second part of fig. 3. The bolt is screwed out, which is actually equivalent to the increase of the support length of the inner support model, the axial force borne by the inner support model is correspondingly increased due to the unchanged width of the diaphragm wall model device 5, and when the reading of the pressure sensor in the middle of the inner support model reaches the value of the prestress to be applied, the bolt 3 is stopped to be screwed outwards, so that the prestress is accurately applied to the inner support.

The length of the whole support is adjusted by screwing in the depth of the bolts at two sides, the length is adjusted when the support is installed, and prestress is applied by controlling the jacking degree of the underground diaphragm wall.

The prestressing force applying method is convenient, but not restrictive, and bolts at two ends can be screwed out respectively.

3) In the foundation pit engineering test, the change condition of the supporting axial force can be continuously measured by the pressure sensor, and an axial force change curve is drawn.

In conclusion, the axial force borne by the support is measured by applying the pressure sensor in the inner support model; the two ends of the support are provided with prestress by screwing the bolts and adjusting the length of the support, and the prestress applied in the inner support is accurately controlled by combining numerical values in the pressure sensor.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. The inner support device capable of accurately applying prestress in foundation pit model test comprises an inner support model main body made of PVC pipes, and is characterized in that a pressure sensor is arranged in the middle of the inner support model main body, bolts which are in threaded connection with the inner support model main body are arranged at two ends of the inner support model main body, the bolts are hinged to a ground connection wall model device during use, the support length of the inner support model is adjusted by screwing the bolts, prestress is applied by adjusting the support length of the inner support model, and the magnitude of the prestress is measured by the pressure sensor.

2. The internal support device capable of accurately applying prestress in foundation pit model test according to claim 1, wherein the pressure sensor is connected with a computer to measure the support shaft force in real time.

3. The internal support device capable of accurately applying prestress in foundation pit model test according to claim 1, wherein a pin shaft hole extending along the length direction of the bolt is arranged at the top of the bolt, and a pin shaft matched with the pin shaft hole is arranged on the diaphragm wall model device.