CN214224784U

CN214224784U - Tunnel lining back cavity simulation loading device

Info

Publication number: CN214224784U
Application number: CN202022738856.2U
Authority: CN
Inventors: 杨梦莹; 李丹阳; 巩晓芸
Original assignee: Shandong University of Science and Technology
Current assignee: Shandong University of Science and Technology
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-09-17
Anticipated expiration: 2030-11-24

Abstract

The utility model discloses a tunnel lining back cavity simulation loading device, which comprises a tunnel structure model arranged between a bottom plate and a top plate, wherein a high-pressure air bag is partially coated outside the tunnel structure model, an external restraint device is arranged outside the high-pressure air bag, and the part of the tunnel structure model which is not coated with the high-pressure air bag is a cavity for simulating; annular resistance strain gauges are symmetrically adhered to the inner surface and the outer surface of the tunnel structure model and communicated with an external strain box through a lead; the high-pressure air bag is connected with an air pump outside the air pipe, and a high-precision absolute barometer is arranged on the air pipe. The invention also discloses a loading method using the device. The utility model discloses can clearly understand back cavity to tunnel structure's influence, see tunnel structure crack and decrease evolution process, the change law of analysis internal force provides the reference for engineering practice.

Description

Tunnel lining back cavity simulation loading device

Technical Field

The utility model belongs to the technical field of the construction, a loading device is related to, especially, relate to a loading device who simulates tunnel lining cavity behind the back.

Background

Most roads and railway tunnels in construction and operation at home and abroad have diseases of different degrees, and cavities at the back of the lining are usually direct causes of the diseases such as lining cracking, water seepage and the like. Due to the influence of factors such as tunnel construction and geological environment, a cavity which is not tightly contacted with surrounding rocks is easily generated between the lining and the surrounding rocks. The existence of cavity seriously influences the interact between lining and the country rock, leads to lining structure bearing capacity not enough and produces stress concentration's phenomenon, causes and aggravates tunnel lining structure damage, and then arouses a series of harm such as infiltration water, freeze injury and reinforcing bar corrosion. The existing technical scheme cannot reasonably analyze the size of the cavity, does not consider the change of the position of the cavity, has the influence on the safety coefficient of the section of the tunnel structure and the like, and is difficult to scientifically analyze and evaluate the diseases of the tunnel.

For example, patent application publication No. CN 105673049 a discloses a tunnel lining back cavity simulation loading device, which is characterized in that the thickness and the outer contour dimension of a tunnel lining are determined by selecting a geometric similarity ratio, and the elastic modulus similarity ratio, the density similarity ratio, the strength similarity ratio and the face load similarity ratio of a tunnel lining material are determined by selecting a stress similarity ratio.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a tunnel lining back cavity simulation loading device and a tunnel lining back cavity simulation loading method.

The utility model discloses a realize through following technical scheme.

A tunnel lining back cavity simulation loading device comprises a tunnel structure model arranged between a bottom plate and a top plate, wherein a high-pressure air bag is partially coated outside the tunnel structure model, an external restraint device is arranged outside the high-pressure air bag, and the part, which is not coated outside the tunnel structure model, of the high-pressure air bag is a cavity simulating cavity; annular resistance strain gauges are symmetrically adhered to the inner surface and the outer surface of the tunnel structure model and communicated with an external strain box through a lead; the high-pressure air bag is connected through the outside air pump of trachea, is provided with the absolute barometer of high accuracy on the gas-supply pipe for the atmospheric pressure size in the accurate control high-pressure air bag to reach the purpose of accurate simulation tunnel country rock.

Furthermore, the tunnel lining back cavity simulation loading device is characterized in that a vent pipe is reserved on the top plate, and wiring ports for leading out wires of inner and outer resistance strain gauges of the tunnel structure model to the outside of the tunnel structure model are symmetrically arranged on the upper surface and the lower surface of the top plate.

Further, the tunnel lining back cavity simulation loading device is characterized in that the geometric similarity ratio of a tunnel structure model is 1: 20-1: 50, and the longitudinal length of the model is 20-30 cm.

Further, tunnel lining back of the body cavity simulation loading device, its characterized in that, roof, bottom plate and outside restraint device all adopt organic glass to make, the top is 2 ~ 3mm lower than the roof.

By the foregoing technical scheme the utility model discloses a can see, the utility model provides a pair of tunnel lining cavity simulation loading device behind one's back, the engineering characteristics of description tunnel prototype that can be accurate can clearly understand behind one's back cavity to tunnel structure's influence, sees tunnel structure crack and decrease evolution process, the change law of analysis internal force, and the establishment of model is more saves time, laborsaving, suitable using widely.

Effectively solve the high problem of required precision among the reinforcing bar mechanical connection, furthest reduces the reinforcing bar and connects the size and mismatch, connect insecure, intensity scheduling problem not up to standard, when accelerating construction speed, guarantees the structural stability of reinforcing bar joint.

The utility model discloses a construction application method is: installing a hole simulation loading device, debugging the instrument, inflating the high-pressure air bag through a vent pipe according to the required surrounding rock pressure after the integral debugging of the instrument is finished, constantly paying attention to the reading of a high-precision absolute barometer, slowing down the inflation speed when the air pressure in the high-pressure air bag is close to the required pressure, and constantly paying attention to the change of the inner surface of the tunnel structure model; when the reading is reached, the inflation is suspended, and the structural condition is observed; then continuing to inflate until the tunnel structure model is damaged; and calculating the final axial force and bending moment for damage according to the difference of the readings of the inner strain gauge and the outer strain gauge, and well recording.

Compared with the prior art, the utility model discloses following beneficial effect has.

1. By the indoor model test method, the crack evolution process of the tunnel structure can be clearly seen, the change rule of internal force is analyzed, the influence of the cavity behind the lining on the tunnel structure is known, and the development of the test research on the crack rule of the lining structure under the condition that the cavity exists in the tunnel has important practical significance and engineering application significance.

2. The equivalent loading method of replacing surrounding rock pressure with air pressure not only can enable the tunnel to be stressed more uniformly, but also can highlight the change rule of the internal force of the tunnel lining structure, and provides scientific and reasonable basis for the design and construction of the lining structure by researching the stress characteristics and the damage process of the tunnel structure.

3. The model is simple to operate, materials are easy to obtain, manpower consumption is reduced, great stress loss cannot be generated, energy consumption is saved, certain flexibility is achieved, proper improvement can be performed on different tunnel lining structure back cavity conditions, and scientific and reasonable basis is provided for design and construction of the tunnel lining structure.

Drawings

Fig. 1 is a schematic perspective view of the present invention.

Fig. 2 is a schematic front view of the structure of the present invention.

FIG. 3 is a schematic diagram of the connection between the tunnel model and the internal and external strain gauges and wires.

FIG. 4 is a schematic view of the air bag externally connected with a vent tube and an air pump.

Illustration of the drawings: 1. an external restraint device. 2. The high-pressure air bag comprises a high-pressure air bag body, 3 parts of a tunnel structure model, 4 parts of a wiring port, 5 parts of an inner surface strain gauge, 6 parts of a vent pipe, 7 parts of a high-precision absolute barometer, 8 parts of an air pump, 9 parts of a bottom plate, 10 parts of a top plate, 11 parts of an outer surface strain gauge, 12 parts of a lead and 13 parts of a gap.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

The structure, ratio, size and the like shown in the drawings attached to the present specification are only used for matching with the content disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the limit conditions of the present invention, so that the present invention has no technical essence, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and the purpose which can be achieved by the present invention. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship may be made without substantial technical changes, and the scope of the present invention may be considered as the scope of the present invention.

As shown in fig. 1 to 4, a tunnel lining back cavity simulation device and method includes: the device comprises a bottom plate 9, a tunnel structure model 3, an external restraint device 1, a high-pressure air bag 2, an air pipe 6, an air pump 8, a high-precision absolute barometer 7, an inner surface strain gauge 5, an outer surface strain gauge 11 and a plurality of wires 12. Annular resistance strain gauges are symmetrically adhered to the inner surface and the outer surface of the tunnel structure model 3, meanwhile, the wires 12 of the inner surface strain gauges 5 are well connected, the wires 12 of the outer surface strain gauges 11 are directly led out, and the wires 12 of the inner surface strain gauges 5 are welded on a strain box in groups and used for reading data. The high-precision absolute barometer 7 is connected with the high-pressure air bag 2 and the air pump 8 and used for accurately controlling the air pressure in the high-pressure air bag 2 so as to achieve the purpose of accurately simulating the tunnel surrounding rock.

When the device is used, after the whole debugging of the device is finished, the high-pressure air bag 2 is inflated through the vent pipe 6 according to the required surrounding rock pressure, the reading of the high-precision absolute barometer 7 is constantly noticed, when the air pressure in the high-pressure air bag 2 is close to the required pressure, the inflation speed is reduced, and the change of the inner surface of the tunnel structure model 3 is constantly noticed; when the reading is reached, the inflation is suspended, and the structural condition is observed; then continuing to inflate until the tunnel structure model 3 is damaged; and calculating the final axial force and bending moment of the damage according to the difference of the readings of the inner strain gauge and the outer strain gauge, and recording.

Claims

1. A tunnel lining back cavity simulation loading device is characterized by comprising a tunnel structure model arranged between a bottom plate and a top plate, wherein a high-pressure air bag is partially coated outside the tunnel structure model, an external restraint device is arranged outside the high-pressure air bag, and the part, which is not coated outside the tunnel structure model, of the high-pressure air bag is a cavity simulating cavity; annular resistance strain gauges are symmetrically adhered to the inner surface and the outer surface of the tunnel structure model and communicated with an external strain box through a lead; the high-pressure air bag is connected with an air pump outside the air pipe, and a high-precision absolute barometer is arranged on the air pipe.

2. The tunnel lining cavity-behind-the-back simulation loading device of claim 1, wherein a vent pipe is reserved on the top plate, and wiring ports for leading out wires of inner and outer resistance strain gauges of the tunnel structure model to the outside of the tunnel structure model are symmetrically arranged on the upper surface and the lower surface of the top plate.

3. The tunnel lining back cavity simulation loading device according to claim 1, wherein the geometric similarity ratio of the tunnel structure model is 1: 20-1: 50, and the longitudinal length of the model is 20-30 cm.

4. The tunnel lining cavity back loading simulation device according to claim 1, wherein the top plate, the bottom plate and the external restraint device are all made of organic glass, and the top of the device is 2-3 mm lower than that of the top plate.