Platform, system and method for simulating critical rock collapse of surrounding rock in underground engineering

A platform, system, and method for simulating critical rock collapse of surrounding rock in underground engineering includes: four vertically arranged reaction walls defining a square reaction space, and a base mounted at a lower end opening of the wall; and a row of horizontally arranged stress loading plates at a side of each wall close to the reaction space, and a reaction beam above this space, where the reaction beam, the stress loading plate, and the base define a loading space, and the loading space is configured for placement of a surrounding rock simulation block to be tested; the stress loading plate capable of moving horizontally in a direction of the reaction wall, and the reaction beam capable of moving in a vertical direction, so as to load the surrounding rock simulation block; and the stress loading plate and the reaction beam being driven by linear motion units for movement.

TECHNICAL FIELD

The present invention belongs to the technical field of geotechnical engineering, in particular to a platform, system, and method for simulating critical rock collapse of surrounding rock in underground engineering.

BACKGROUND

In China, with the booming of infrastructure construction such as transportation, energy, and hydraulic engineering, underground construction represented by tunnels, underground powerhouses, underground complexes, and the like has come into high-speed period of development. The critical rock collapse of surrounding rock in underground engineering is a major threat to safety construction of underground engineering. Since 2005, more than 300 cases of critical rock collapse have been reported, ranging from mechanical damage to project delay, and even more serious casualties and heavy economic losses. The theoretical and technical challenges to disaster prevention and control research are unclear evolution mechanism and lack of reliable disaster source positioning and forecasting and early warning equipment for the critical rock collapse of surrounding rock.

As far as the inventor knows that there is no simulation test instrument for the critical rock collapse of surrounding rock in underground engineering at home and abroad currently, and it is unable to provide a reliable experimental platform for new theories and new industrial research, which is the major factor severely limiting the revealing of disaster evolution mechanism and the development of positioning and early warning technologies.

SUMMARY

The present invention aims to provide a platform, system, and method for simulating critical rock collapse of surrounding rock in underground engineering, which can realize simulation tests for the collapse mechanism and law of critical rock collapse of surrounding rock in underground engineering.

In order to achieve the above objective, a first aspect of the present invention provides a platform for simulating critical rock collapse of surrounding rock in underground engineering, including four vertically arranged reaction walls. The reaction walls define a square reaction space, and a base is mounted at a lower end opening of the reaction wall.

A row of horizontally arranged stress loading plates are disposed at a side of each reaction wall close to the reaction space, and a reaction beam is disposed above the reaction space; and the reaction beam, the stress loading plate, and the base define a loading space, and the loading space is configured for placement of a surrounding rock simulation block to be tested.

The stress loading plate can move horizontally in a normal direction of the reaction wall, and the reaction beam can move in a vertical direction, so as to load the surrounding rock simulation block. The stress loading plate and the reaction beam are respectively driven by linear motion units for movement.

As a further limitation to the first aspect of the present invention, an opening is provided on the base, a lower part of the base is provided with a basement, an arch is disposed in the basement, and the arch can be lifted in a vertical direction to transfer the arch between the basement and the loading space.

As a further limitation to the first aspect of the present invention, there are a plurality of the arches, the plurality of arches can be lifted in a vertical direction separately, a vertically arranged lifting mechanism is disposed between the arch and a lower bottom surface of the basement, and the lifting mechanism is configured to drive the arch to lift.

A second aspect of the present invention provides a system for simulating critical rock collapse of surrounding rock in underground engineering, including the platform for simulating critical rock collapse of surrounding rock in underground engineering, and further including a simulation system. The simulation system includes a holographic projection device, a control device, and the surrounding rock simulation block. A sensor is mounted in the surrounding rock simulation block, the sensor is configured to transmit information of the surrounding rock simulation block when being loaded to the control device, a three-dimensional model of the surrounding rock simulation block is prestored in the control device, and the control device can change the three-dimensional model according to the information from the sensor.

The holographic projection device can complete projection of the three-dimensional model in space according to the information transmitted by the control device.

A third aspect of the present invention provides a test method for simulating critical rock collapse of surrounding rock in underground engineering, including:

starting a control device to control stress loading plates to synchronously advance and arches to synchronously rise to form a semi-enclosed space together with the base;

prefabricating a surrounding rock simulation block in the semi-enclosed space, burying a sensor in rock mass, connecting the sensor and the control device to start to obtain internal displacement and stress state information of the rock mass, and after the prefabrication is completed, performing routine maintenance, and waiting for a material strength to meet design requirements;

mounting and starting a multi-physics field information monitoring device such as an infrared camera and an acoustic emission monitor at a set location, and starting a holographic projection device to project an initial state of a rock mass structure of the surrounding rock simulation block;

controlling the stress loading plate to apply a stress load to the surrounding rock simulation block by layers with a stable applied pressure, waiting for multi-physics field information of the surrounding rock simulation block to stabilize again, and then starting a next step;

drilling a hole above an arch contour line of the surrounding rock simulation block, burying a blasting simulation device in the surrounding rock simulation block and connecting the blasting simulation device to the control device, simulating a single blasting vibration, and meanwhile successively sinking a lifting arch to a basement in a simulated excavation direction;

before and after the sinking of the lifting arch each time, monitoring a multi-physics field state change process of the rock mass structure, and after a multi-physics field state is stable, raising the sunk lifting arch to a centimeter below a rock surface to prevent casualties and instrument damage caused by rock collapse; and starting a next cycle of excavation simulation and monitoring until all excavation is completed.

The foregoing one or more technical solutions have the following beneficial effects:

1. With the cooperation of the stress loading plate and the reaction beam, the physical test simulation of real-scale rock mass structure excavation is realized at a three-dimensional level.

2. The mechanical effect of displacement constraint release and the vibration effect of blasting in an excavation process of underground engineering is simulated really, and a gradual excavation dynamic process of underground engineering is accurately controlled, so as to accurately simulate an internal dynamic response of surrounding rock in the excavation process.

3. The stress loading plates disposed in layers can provide a hardware basis for accurate simulation of ground stress gradient distribution, and by controlling the stress loading plate to stretch, steps for walking and a platform for standing are provided for test personnel to enter a test area to carry out operations such as sensing element burying.

4. The holographic projection device is used to comprehensively display an excavation process of underground engineering and a development-instability dynamic process of a critical rock structure, which is more intuitive and easy to understand compared with data post-processing analysis of two-dimensional charts of traditional computers, thus providing a technical support for the thorough understanding and deep digging of test laws and for the prediction and early warning of critical rock disasters.

DETAILED DESCRIPTION

It should be noted that, the following detailed descriptions are all exemplary, and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs.

It should be noted that terms used herein are only for describing specific implementations and are not intended to limit exemplary implementations according to the present invention. As used herein, the singular form is also intended to include the plural form unless the context clearly dictates otherwise. In addition, it should further be understood that, terms “comprise” and/or “include” used in this specification indicate that there are features, steps, operations, devices, components, and/or combinations thereof.

For convenience of description, the words “above”, “below”, “left”, and “right” only indicate directions consistent with those of the accompanying drawings, are not intended to limit the structure, and are used only for ease and brevity of illustration and description, rather than indicating or implying that the mentioned device or element needs to have a particular orientation or needs to be constructed and operated in a particular orientation. Therefore, such terms should not be construed as a limitation on the present invention.

This embodiment provides a platform for simulating critical rock collapse of surrounding rock in underground engineering, as shown inFIGS.1-2, including four vertically arranged reaction walls1. The reaction walls1define a square reaction space, and a base3is mounted at a lower end opening of the reaction wall1.

A row of horizontally arranged stress loading plates5are disposed at a side of each reaction wall1close to the reaction space, and a reaction beam is disposed above the reaction space. The reaction beam, the stress loading plate5, and the base3define a loading space, and the loading space is configured for placement of a surrounding rock simulation block to be tested.

The stress loading plate5can move horizontally in a normal direction of the reaction wall1, and the reaction beam can move in a vertical direction, so as to load the surrounding rock simulation block.

The stress loading plate5and the reaction beam are respectively driven by linear motion units for movement.

Each group of stress loading plates5include a plurality of layers of horizontally arranged loading plate members, and each loading plate member is driven by one linear motion unit to realize layered loading of the surrounding rock simulation block in a horizontal direction.

An opening is provided on the base3, a lower part of the base3is provided with a basement4, an arch7is disposed in the basement4, and the arch7can be lifted in a vertical direction to transfer the arch7between the basement4and the loading space.

There are a plurality of the arches7, the plurality of arches7can be lifted in a vertical direction respectively, a vertically arranged lifting mechanism is disposed between the arch7and a lower bottom surface of the basement4, and the lifting mechanism is configured to drive the arch7to lift.

A shape of the arch7is set as that an upper contour shape of the arch7is the same as a lower contour shape of the surrounding rock simulation block, and the arch7is configured to support the surrounding rock simulation block.

There are a plurality of the reaction beams, and a distance between adjacent reaction beams is adjustable.

This embodiment provides a system for simulating critical rock collapse of surrounding rock in underground engineering, as shown inFIGS.1-5, including a reaction wall1, a reaction beam2, a base3, a basement4, a stress loading plate5, a hydraulic cylinder6, a lifting arch7, a blasting simulation device8, a data analysis and control center9, an outer wall10, an air partition11, and a holographic projection device12. The reaction wall1, the base3, and the basement4jointly form a semi-enclosed space with an open top, into which a semi-enclosed space with an open top jointly formed by the stress loading plate5and the lifting arch7is nested to internally accommodate a prefabricated surrounding rock structure. The outer wall10is built in an axial extension direction by relying on a front side surface of the reaction wall1. The holographic projection device12is contained in the outer wall10.

The reaction force walls1are arranged on front, rear, left, and right sides, and overlap each other. The reaction beam2is mounted on a top of the reaction wall1, with two ends respectively overlapped on tops of the reaction walls1at the front and rear, and can move left and right along a top edge of the reaction wall1. The base3is surrounded by the reaction wall1, and the base3is hollowed out partially along a longitudinal axis of symmetry. A width of the hollowed-out area is slightly larger than a left-right width of the lifting arch7. The basement4is located below the base3, communicated with the hollowed-out area of the base3, and has a length and a width that are consistent with the hollowed-out area, and a depth that is the sum of a height of the lifting arch7and a height of the hydraulic cylinder6after contraction.

The stress loading plates5are divided into stress loading plates and vertical stress loading plates. A plurality of rows of hydraulic cylinders6are mounted on inner surfaces of the reaction walls1at the four sides in a horizontal row-column direction. A piston rod of the hydraulic cylinder6points into an enclosed area in a normal direction of the reaction wall1. A top of the piston rod is connected to a back of the stress loading plate to drive the stress loading plate to move in the normal direction of the reaction wall1. The stress loading plates are laid in layers in a horizontal direction. A hydraulic cylinder6with a piston rod pointing downwards is mounted on a lower surface of the reaction beam2, and the piston rod is connected to a back of a vertical loading plate to drive the vertical loading plate to move in a vertical direction up and down.

A bottom surface of the basement4is provided with a plurality of rows of hydraulic cylinders6distributed in a left-right direction. The hydraulic cylinder6is buried in the bottom surface of the basement4and connected upwards to the lifting arch7to support the lifting arch to move vertically through the basement4and the base3. The blasting simulation device8is an independent carrying structure buried in the prefabricated surrounding rock.

The data analysis and control center9adopts a high-performance computer as a carrier, on which control software for various instrument parts and processing and analysis software for acquired multivariate data are mounted to realize dynamic control of a whole test process and real-time state analysis of a test body.

The outer wall10is built by relying on a front end side surface of the reaction wall1to extend forwards. The air partition11is disposed inside the outer wall10to block dust generated by the test within the reaction wall1and a rear half of the outer wall10. The holographic projection device12is arranged in a front half in the outer wall10. The holographic projection device12is arranged axially in a front-rear direction, and projects in an area near a central axis to generate a rock mass structure model. The holographic rock mass model changes synchronously with a test operation, so as to dynamically display surrounding rock excavation and critical rock development-instability processes.

This embodiment provides a test method for simulating critical rock collapse of surrounding rock in underground engineering, including:

A. A data analysis and control center9is started to control stress loading plates5to synchronously advance and lifting arches7to synchronously rise to form a semi-enclosed space together with the base3.

B. A cubic rock mass structure is prefabricated in the semi-enclosed space, and a sensing element such as a pressure cell and a gyroscope is buried into rock mass according to design requirements of a test plan. The sensing element is connected to the data analysis and control center9to start to acquire internal displacement and stress state information of the rock mass. After the prefabrication is completed, routine maintenance is performed, waiting for a material strength to meet design requirements.

C. A multi-physics field information monitoring device such as an infrared camera and an acoustic emission monitor is mounted and started at a set location, and an air partition11and a holographic projection device12are started to project an initial state of a rock mass structure.

D. According to a design ground stress environment, a hydraulic cylinder6is controlled to push the stress loading plate5to apply a stress load to the rock mass by layers, with an applied pressure kept stable, waiting for multi-physics field information of the rock mass to stabilize again, and then a next step is started.

E. A hole is drilled above an arch contour line of the rock mass, and a blasting simulation device8is buried and connected to the data analysis and control center9. A single blasting vibration is simulated, and meanwhile a lifting arch7is successively sunk to a basement4in a simulated excavation direction (the quantity of arches sunk each time is determined by an excavation simulation plan).

F. Before and after the sinking of the lifting arch7each time, a multi-physics field state change process of the rock mass structure is monitored. After a multi-physics field state is stable, the sunk lifting arch7is raised to a centimeter below a rock surface to prevent casualties and instrument damage caused by rock collapse.

G. A next cycle of excavation simulation and monitoring is started until all excavation is completed.

H. In a whole test process, data results acquired by the sensing element and monitoring equipment in real time are analyzed and dug to analyze state changes of the rock mass structure; and excavation and surrounding rock exposure is displayed in the holographic projection model synchronously with test excavation, a critical rock structure is specially identified according to analysis results, and its state parameter change trend is displayed, thus laying a data foundation for revealing evolution law of critical rock disasters of surrounding rock, and realizing positioning and quantitative identification of the critical rock structure and disaster early warning.

The specific implementations of the present invention are described above with reference to the accompanying drawings, but are not intended to limit the protection scope of the present invention. A person skilled in the art should understand that various modifications or deformations may be made without creative efforts based on the technical solutions of the present invention, and such modifications or deformations shall fall within the protection scope of the present invention.