Tunnel step-by-step excavation simulation device and using method
Technical Field
The invention belongs to the field of tunnel stress simulation experiments, and particularly relates to a tunnel step-by-step excavation simulation device and a use method thereof.
Background
With the increasing population, the accelerating speed of urbanization and the increasing of the living standard of people, the situations of housing difficulty, difficult traveling and the like gradually appear in many large cities, so that the space utilization of people is gradually changed from the ground to the underground. Meanwhile, the mountaineering and water-crossing are also realized in the process of gradual development of the transportation network in China, and convenience is provided for road construction by frequently building mountaineering tunnels. Therefore, the underground engineering construction in China has entered into a prosperous period at present, and underground engineering such as railway tunnels, high-speed railway tunnels, highway tunnels, subway tunnels, hydraulic tunnels, comprehensive pipe galleries and the like have several or even dozens of under-construction projects. The indispensable part of these projects is the excavation of tunnels in the initial construction, and the process can be continued only after the smooth completion of the project. Under the conditions that the geological conditions are complex and direct blasting excavation is not easy to realize, the construction method of step excavation is often adopted to reduce disturbance to rock and soil mass and prevent larger problems in the construction process. Therefore, the construction method of step-by-step excavation is common in the construction of daily underground engineering.
Therefore, in the distributed excavation construction process of the tunnel, the reasonability of the design parameters is determined, and whether the selected construction method can ensure the stability of the tunnel surrounding rock is significant. However, most of the existing simulation methods utilize software to perform two-dimensional digital analysis and simulation, have no entity, and cannot perform materialized simulation on actual conditions, and meanwhile, the modeling and analysis steps are complex and need a certain operation basis, and the existing entity simulation tunnels cannot perform precise working condition simulation.
Disclosure of Invention
The invention aims to provide a tunnel step-by-step excavation simulation device and a using method, which can simulate the tunnel step-by-step excavation construction process and monitor the data of stress, deformation, displacement and the like of other positions of a tunnel under the influence of disturbance generated in the tunnel step-by-step excavation construction process; accurate data are obtained through a measuring instrument and various monitoring devices, and basis is provided for determining reasonability of design parameters, determining whether the selected construction method can ensure stability of tunnel surrounding rocks and the like. The problems that an existing simulation device has no entity, can not perform materialized simulation on actual conditions, is complex in modeling analysis steps, needs a certain operation foundation and the like are solved, and the simulation device has the characteristics of simple structure, low cost, convenience in operation and wide applicability, and has wide engineering practice significance and application prospect.
In order to realize the technical characteristics, the invention adopts the technical scheme that: a step-by-step excavation simulation device for a tunnel comprises a simulation tunnel with a hollow structure, wherein a rock mass simulation layer is filled in the simulation tunnel; a blasting simulation device is embedded in the rock mass simulation layer and comprises an electromagnetic layer which is a hollow cylinder structure consisting of electromagnets; the electromagnetic layer is connected with an external electromagnet strength controller; the gap of the rock mass simulation layer is filled with expansion cement, and a heating wire is embedded in the expansion cement; a plurality of data collecting devices are arranged in the gaps of the rock mass simulation layer and at the junctions of the rock mass simulation layer and the simulation tunnels; and a sound wave instrument is arranged outside the simulated tunnel.
Preferably, the rock mass simulation layer comprises a plurality of rock mass simulation blocks stacked on each other.
Preferably, the blasting simulation device further comprises a plurality of magnets buried in the boundary between the inner wall of the simulated tunnel and the rock mass simulation layer, and the magnets and the electromagnetic layer are magnetically attracted; the strength controller of the electromagnet selects a unidirectional variable frequency power supply of the Nissan-free Nassi electronics technology Co., Ltd, the model of ANB11-0.5KV, and the strength of the magnetic force of the electromagnet is changed by adjusting the magnitude of the output current.
Preferably, the number of the electromagnetic layers is multiple, the electromagnetic layers are not mutually contacted, and each electromagnetic layer is independently connected with the electromagnet strength controller; the outer surface of the electromagnetic layer is wrapped with a rigidity adjusting layer formed by concrete, and the rigidity adjusting layer is wrapped with waterproof cloth.
Preferably, the data collection device comprises a multipoint displacement meter, one side of the multipoint displacement meter is pasted with a strain gauge, and the other side of the multipoint displacement meter is pasted with a pressure sensor; the pressure sensor, the strain gauge and the multipoint displacement meter are wrapped into a data collection device through waterproof cloth; a plurality of data collection device pastes at a plurality of rock mass simulation piece surfaces, and a rock mass simulation piece surface sets up a data collection device at most.
Preferably, the outer surfaces of the rock mass simulation blocks are coated with organic glue; organic glue is also coated at the junction of the rock mass simulation layer and the simulation tunnel; and filling expansion cement in the gap of the rock mass simulation block coated with the organic glue.
Preferably, the use method of the tunnel step-by-step excavation simulation device comprises the following steps:
step 1: surveying in the field: determining the size of an actually required tunnel excavation area through field survey, scaling down according to the proportion of 10: 1-15: 1, and determining the size of a simulated tunnel; performing component analysis and strength test by collecting the original rock on site, and determining the strength and the component proportion of the simulated original rock;
step 2: matching simulated rock mass blocks: according to the measured compressive strength and component proportion of the simulated original rock, manufacturing a rock mass simulation block by using cement, sand, mica sheets, gypsum and water; the strength of the simulated rock mass block is properly reduced by increasing the cement proportion and reducing the proportion of sand and mica sheets, or the strength of the simulated rock mass block is properly increased by increasing the proportion of sand and mica sheets, so that the strength of the simulated rock mass block is finely adjusted to be close to the strength parameter of actual original rock as much as possible;
step 3: pouring a rock mass simulation block: pouring the proportioned simulated rock mass ingredients by using the manufactured template; the length of the longest edge of the poured rock mass simulation block is 15% -20% of the width of the bottom edge of the simulation tunnel;
step 4: manufacturing of a simulation device and arrangement of monitoring instruments: firstly, manufacturing a hollow tunnel model, coating organic glue on the boundary of a simulated tunnel, and sticking a plurality of magnets on the surface of the organic glue;
then filling rock mass simulation blocks coated with organic glue on the outer surfaces layer by layer from bottom to top in the simulation tunnel to form a rock mass simulation layer; when the height of the material is half of the height, embedding a plurality of electromagnetic layers, wherein the number of the electromagnetic layers is the same as the expected number of times of simulated blasting; then, continuously filling the rock mass simulation block until the simulation tunnel is filled; in the filling process, when one layer of rock mass simulation blocks are filled, expansion cement is injected into gaps among the rock mass simulation blocks, and heating wires are distributed in the expansion cement; meanwhile, randomly sticking a data collection device on the surface of a part of rock mass simulation block; each electromagnetic layer is independently connected with an electromagnet strength controller through a lead wire which extends out; placing a sound wave instrument outside the simulated tunnel;
finally, heating the expansion cement through a heating wire, so that the expansion cement expands in the gap of the rock mass simulation block, and applying pressure to the rock mass simulation block to simulate the stress in the rock mass;
step 5: simulating excavation: after the internal stress of the simulation device is stable, performing simulation excavation on the tunnel step by step;
firstly, the strength of magnetism of one section of the electromagnetic layer is adjusted through an electromagnet strength controller, so that the section of the electromagnetic layer and the nearest magnet arranged at the boundary of the simulated tunnel and the rock mass simulated layer around the electromagnetic layer attract each other, the magnet at the boundary exerts external force on the rock mass simulated layer at the section, internal stress change of the rock mass simulated layer is caused, a rock mass simulated block is promoted to fall off at a certain speed, and the process of destroying the internal stress of the rock mass through blasting in actual excavation is simulated; each electromagnetic layer can be independently controlled, so that the process of multiple blasting can be simulated;
then smearing the organic glue solution at the gap of the rock mass simulation layer of the part to be excavated by a needle cylinder, dissolving the organic glue adhered to the surface of the rock mass simulation block, dropping off the part of the rock mass simulation block, and taking out the dropped rock mass simulation block to simulate rock mass excavation; the liquid outlet at the front end of the needle cylinder is connected with a brush, so that organic glue solution can be conveniently and uniformly coated;
step 6: data monitoring and analysis: the stress, strain and displacement of each part in the step-by-step excavation process are monitored by a pressure sensor and a multipoint displacement meter, and the normal stress and the shear stress of each part can be calculated according to the measured value of a strain gauge adhered to the surface of the simulated rock mass; performing rock mass sound wave test by using a sound wave instrument to detect the quality change of the rock mass simulation block; the data is further analyzed, and when the stress borne by the simulated rock mass is enlarged according to the proportion of the actual excavation tunnel and the simulated tunnel according to the conditions and exceeds the bonding force of the actual soil body, the rock-soil body at the actual construction position is affected to loosen or fall off; when a large stress concentration suddenly appears at a certain position in the simulated tunnel or the simulated rock block obviously deforms, the excavation mode has certain risk, the blasting frequency and the like can be determined again; meanwhile, a creep or deformation curve of the rock body at the fixed position along with excavation can be drawn according to the monitoring information, so that the disturbance and influence of different excavation modes, excavation speeds and the like on the rock body at other parts can be determined.
Preferably, in the step5, the softening effect after water bubbles in construction and the deterioration of the rock mass under different working conditions such as loosening and falling of the rock mass after blasting can be simulated by controlling the dissolving range.
Preferably, in the step5, the temperature of the heating wire can be increased to make ettringite as a main component in the expansion cement lose water and deform, so that the bearing capacity of the expansion cement is lost, and the condition that the internal stress of the rock body is disturbed can be simulated.
The invention has the following beneficial effects:
1. the step-by-step excavation of the tunnel can be accurately simulated through the rock mass simulation block poured according to the matching proportion determined by the strength of the original rock, meanwhile, the method for simulating excavation is determined according to different disturbance conditions during excavation, and the speed of simulating excavation can be accurately controlled by adjusting the strength of the electromagnet;
2. the device adopts the organic glue dissolving solution to dissolve the organic glue to simulate excavation, and meanwhile, the dissolving speed, the position and the amount of the added dissolving agent can be accurately controlled. The expansion cement is adopted to simulate the internal stress of the rock mass, and the affected range, the changed size, the changed speed and the like of the affected stress can be controlled. The electromagnetic layer is adopted to simulate the sudden falling of the rock mass during blasting, and the range, falling speed and the like of the electromagnetic layer can be controlled;
3. the stress, strain and displacement of each part in the step-by-step excavation simulation process are monitored through the pressure sensor, the strain gauge and the multipoint displacement meter, and the stress is calculated. The data are further analyzed, and meanwhile, a creep deformation or deformation curve of the rock body at the fixed position along with excavation can be drawn according to the monitoring information, so that the disturbance and influence of different excavation modes, excavation speeds and the like on the rock body at other parts are determined, and the safety degree and the like are judged.
Drawings
The invention is further illustrated by the following figures and examples.
FIG. 1 is a schematic view of the overall apparatus according to the present invention;
FIG. 2 is a schematic view of the fitting manner of the rock mass simulation block according to the present invention;
FIG. 3 is a schematic view of a solution adder according to the present invention;
the reference numbers in the figures are: the device comprises a simulated tunnel 1, a rock mass simulation block 2, an electromagnetic layer 3, a rigidity adjusting layer 6, organic glue 8, expansion cement 9, organic glue dissolving liquid 10, a needle cylinder 12, a brush 13, a heating wire 14, a pressure sensor 15, a strain gauge 16 and a multipoint displacement meter 17.
Detailed Description
In fig. 2, (a) illustrates a V-shaped fitting manner of the rock mass simulation block 2; (b) the figure describes the Z-shaped embedding mode of the rock mass simulation block 2; compared with the rock mass simulation block 2 with the arc or linear surface, the rock mass simulation block 2 designed by adopting the two embedded shapes has good limiting capacity when being contacted and matched with each other, and the stability of the whole structure is greatly improved; when the rock mass simulation block 2 is poured, one or two embedding modes can be selected to prefabricate the pouring template of the rock mass simulation block 2.
Embodiments of the present invention will be further described with reference to fig. 1 to 3.
A tunnel step-by-step excavation simulation device and a using method thereof comprise a simulation tunnel 1 made of toughened glass, wherein rock mass simulation blocks 2 which are matched with each other through V-shaped embedding and Z-shaped embedding and simulate the strength of original rock are arranged in the simulation tunnel 1 according to a preset excavation mode; meanwhile, an electromagnetic layer 3 consisting of electromagnets with concrete outside is arranged at the position of the affected boundary in a segmented mode during blasting, and magnets are arranged outside the electromagnetic layer 3 and work with the electromagnets in a matched mode; filling organic glue 8 between contact surfaces, filling expansion cement 9 in the simulated rock mass to enable the simulated rock mass to bear force, arranging a pressure sensor 15, a strain gauge 16 and a multipoint displacement meter 17 at a selected monitoring position, and arranging an acoustic wave instrument outside the simulated rock mass; and monitoring the stress, deformation, strain, creep, displacement and other data of other positions of the simulated tunnel 1 under the influence of disturbance generated in the whole simulated excavation process in the simulated excavation process.
Furthermore, the toughened glass can be used for achieving the purpose of simulating partial visibility of the condition of the side wall inside the tunnel 1.
Further, the mix proportion of the rock mass simulation blocks 2 arranged in the simulation tunnel 1 is determined according to the original rock strength and the component ratio of the actually simulated distributed excavation area, and the compressive strength of the rock mass simulation blocks is similar to the original rock as much as possible and cannot be larger than the original rock, so that the situation that the safety of the excavation method determined according to the result cannot be guaranteed due to the fact that the disturbance measured by simulation is smaller than the actual situation is avoided.
Furthermore, the whole body of the rock mass after blasting can be suddenly dropped by dropping the electromagnetic layer 3 after power failure, the dropping speed can be controlled according to the current weakening speed, and the influence on the lower rock mass is reduced when the dropping speed is reduced; the strength controller of the electromagnet selects a unidirectional variable frequency power supply of the Nissan-free Nassi electronics technology Co., Ltd, the model of ANB11-0.5KV, and the strength of the magnetic force of the electromagnet is changed by adjusting the magnitude of the output current.
Furthermore, the rigidity adjusting layer 6 outside the electromagnetic layer 3 can adjust the overall rigidity of the electromagnetic layer 3, so that the rigidity of the electromagnetic layer is closer to that of the rock mass simulation block 2 than that of the electromagnetic layer when the electromagnet is directly used, the influence on excavation simulation is reduced, and the simulation result is closer to the real situation.
Further, organic glue 8 is used for filling between rock mass simulation piece 2 and the simulation tunnel 1 to guarantee that its atress is even, be close to the atress of the regional rock mass of waiting to excavate under the actual conditions, its composition can be the easy soluble cemented matter such as organic silica gel, organic glass glue, makes the operation simpler and easier, save time, can simulate the degradation of rock mass under the different operating modes such as the softening effect after the bubble and the rock mass is become flexible after the blasting come-off when having water in the construction simultaneously through dissolving organic glue 8.
Further, the organic glue dissolving solution 10 is used for dissolving the organic glue 8, the main components of the organic glue dissolving solution are a surfactant, a penetrating agent, an organic solvent and the like, and meanwhile, a thickening substance can be added into the organic glue dissolving solution to reduce the fluidity of the organic glue dissolving solution, so that the influence on the connection of other unplanned simulated excavation areas due to the flowing diffusion of the dissolving solution, which influences the accuracy of a test result.
Further, the organic glue solution 10 can control the amount of the solution used each time through the needle cylinder 12, and simultaneously control the area contacting the solution each time through the brush 13 connected to the front end outlet of the needle cylinder 12, so as to avoid affecting the connection of other areas where simulation excavation is not planned, which may affect the accuracy of the test result.
Furthermore, the expansive cement 9 is used for simulating the internal stress of the rock mass, and is injected gradually when the rock mass simulation block 2 is placed in the rock mass simulation block, and meanwhile, the expansive cement 9 is required to be ensured to have no large gap around when being expanded by adding water so as to be expanded in a single direction, and the surrounding rock mass simulation block 2 can bear force after being expanded by adding water.
Furthermore, the heating wire 14 is used for heating the expansive cement 9, so that the main component ettringite in the expansive cement 9 loses water and loses bearing capacity after deformation, the internal stress of the rock is simulated to be disturbed, the temperature and the temperature rising rate of the heating wire 14 can be regulated and controlled according to the power of the heating wire 14, the stress is regulated and reduced, and meanwhile, as the weight loss rate of the ettringite is 33% at the temperature of 135 ℃ and the ettringite becomes anhydrous mineral at the temperature of 700 ℃, all the expansive agents can be influenced by the heating wire 14, and the temperature of the expansive agents is at least above 135 ℃.
Further, pressure sensor 15, foil gage 16 and multiple spot displacement meter 17 can set up according to actual conditions between simulation tunnel 1 hole wall and rock mass simulation piece 2, and its quantity unilateral should not be less than three and can increase according to the requirement to the experimental accuracy degree, can add monitoring instrument in easily being disturbed the region simultaneously.
Furthermore, the acoustic wave instrument can be used for carrying out rock mass acoustic wave test, detecting the quality change of the rock mass simulation block 2 under the condition of no excavation disturbance, and monitoring whether obvious cracks appear in the internal rock mass simulation block 2 in the simulation process or not.
The device and the method for simulating the stepwise excavation of the tunnel comprise the following steps:
step 1: surveying in the field: determining the size of an actually required tunnel excavation area through field survey, carrying out scale reduction according to the proportion of 10:1, and determining the size of a simulated tunnel 1; performing component analysis and strength test by collecting the original rock on site, and determining the strength and the component proportion of the simulated original rock;
step 2: matching simulated rock mass blocks: according to the measured compressive strength of the simulated original rock of 30MPa, the component proportion is 174kg/m3271kg/m of cement3116kg/m of mica sheet37.7kg/m of gypsum3670kg/m of sand3Preparing slurry of the simulated rock mass block 2 according to the component ratio; the strength of the simulated rock mass block 2 is properly adjusted by changing the proportion of cement, sand and mica sheets so as to be close to the parameters of actual original rock as much as possible;
step 3: pouring a rock mass simulation block: pouring the proportioned ingredients by using the manufactured template; the longest side length of the poured rock mass simulation block 2 is 15% -20% of the width of the simulation tunnel 1;
step 4: manufacturing of a simulation device and arrangement of monitoring instruments: firstly, manufacturing a hollow tunnel model, coating organic glue 8 on the boundary of a simulated tunnel 1, and sticking a plurality of magnets on the surface of the organic glue 8;
then filling the rock mass simulation blocks 2 coated with the organic glue 8 on the outer surfaces from bottom to top in the simulation tunnel 1 layer by layer to form a rock mass simulation layer; when the height of the material is half of the height, a plurality of electromagnetic layers 3 are embedded, and the number of the electromagnetic layers 3 is the same as the expected number of times of simulated blasting; then, continuously filling the rock mass simulation block 2 until the simulation tunnel 1 is filled; in the filling process, when filling one layer of rock mass simulation blocks 2, injecting expansion cement 9 into gaps among the rock mass simulation blocks, and simultaneously arranging heating wires 14 in the expansion cement 9; meanwhile, a data collecting device is randomly stuck on the surface of a part of the rock mass simulation block 2; each electromagnetic layer 3 is independently connected with an electromagnet strength controller through a lead wire which extends out; placing a sound wave instrument outside the simulated tunnel 1;
finally, the expansion cement 9 is heated through a heating wire 14, so that the expansion cement 9 expands in the gap of the rock mass simulation block 2, and pressure is applied to the rock mass simulation block 2 to simulate the stress in the rock mass;
step 5: simulating excavation: after the internal stress of the simulation device is stable, performing simulation excavation on the tunnel step by step;
firstly, the strength of magnetism of one section of the electromagnetic layer 3 is adjusted through an electromagnet strength controller, so that the section of the electromagnetic layer 3 and the nearest magnet arranged at the boundary of the simulation tunnel 1 and the rock mass simulation layer around the electromagnetic layer are mutually attracted, the magnet at the boundary exerts external force on the rock mass simulation layer at the section, internal stress change of the rock mass simulation layer is caused, the rock mass simulation block 2 is promoted to fall off at a certain speed, and the process of destroying the internal stress of the rock mass through blasting in actual excavation is simulated; each electromagnetic layer 3 can be independently controlled, so that the process of multiple blasting can be simulated;
then smearing the organic glue solution 10 at the gap of the rock mass simulation layer of the part to be excavated through a syringe 12, dissolving the organic glue 8 adhered to the surface of the rock mass simulation block 2, dropping off the part of the rock mass simulation block 2, and taking out the dropped rock mass simulation block 2 to simulate rock mass excavation; a liquid outlet at the front end of the needle cylinder 12 is connected with a brush 13, which is convenient for evenly coating the organic glue solution 10;
step 6: data monitoring and analysis: the stress, strain and displacement of each part in the step-by-step excavation process are monitored by a pressure sensor 15 and a multipoint displacement meter 17, and the normal stress and the shear stress of each part can be calculated according to the measured value of a strain gage 16 adhered to the surface of a simulated rock mass; performing rock mass sound wave test by using a sound wave instrument to detect the quality change of the rock mass simulation block; the data is further analyzed, and when the stress borne by the simulated rock mass is expanded according to the proportion of the actual excavation tunnel and the simulated tunnel 1 according to the conditions and exceeds the bonding force of the actual soil body, the rock mass at the actual construction position can be affected to loosen or fall off; when a large stress concentration suddenly appears at a certain position in the simulated tunnel 1 or the simulated rock stratum generates obvious deformation, the excavation mode has certain risk, the blasting frequency and the like can be determined again; meanwhile, a creep or deformation curve of the rock body at the fixed position along with excavation can be drawn according to the monitoring information, so that the disturbance and influence of different excavation modes, excavation speeds and the like on the rock body at other parts can be determined.
Furthermore, in the step5, the softening effect after water bubbles in construction and the deterioration of the rock mass under different working conditions such as loosening and falling of the rock mass after blasting can be simulated by controlling the dissolving range.
Furthermore, in step5, the temperature of the heating wire 14 can be increased to make the main component ettringite inside the expansion cement 9 lose water and deform, so that the expansion cement 9 loses the bearing capacity, and the condition that the internal stress of the rock body is disturbed can be simulated.
The above-described embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the present invention, and features in the embodiments and examples in the present application may be arbitrarily combined with each other without conflict. The protection scope of the present invention is defined by the claims, and includes equivalents of technical features of the claims. I.e., equivalent alterations and modifications within the scope hereof, are also intended to be within the scope of the invention.