WO2020259637A1 - 一种深地工程原位应力场和渗流场超重力模拟系统 - Google Patents

一种深地工程原位应力场和渗流场超重力模拟系统 Download PDF

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Publication number
WO2020259637A1
WO2020259637A1 PCT/CN2020/098292 CN2020098292W WO2020259637A1 WO 2020259637 A1 WO2020259637 A1 WO 2020259637A1 CN 2020098292 W CN2020098292 W CN 2020098292W WO 2020259637 A1 WO2020259637 A1 WO 2020259637A1
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Prior art keywords
pressure
seepage
field
pore water
control unit
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PCT/CN2020/098292
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English (en)
French (fr)
Inventor
徐文杰
詹良通
陈云敏
李珂
李金龙
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浙江大学
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Priority to JP2021557728A priority Critical patent/JP7169605B2/ja
Publication of WO2020259637A1 publication Critical patent/WO2020259637A1/zh
Priority to US17/544,966 priority patent/US11385159B2/en

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
    • E02D1/025—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil combined with sampling
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/022—Investigation of foundation soil in situ before construction work by investigating mechanical properties of the soil
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ
    • E02D1/02—Investigation of foundation soil in situ before construction work
    • E02D1/027—Investigation of foundation soil in situ before construction work by investigating properties relating to fluids in the soil, e.g. pore-water pressure, permeability
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G01N15/0806—Details, e.g. sample holders, mounting samples for testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G01N15/082—Investigating permeability by forcing a fluid through a sample

Definitions

  • the invention relates to a physical simulation test system in the field of geotechnical engineering, in particular to a supergravity simulation system for in-situ stress field and seepage field in deep ground engineering.
  • Deep earth engineering refers to the construction process of deep earth structures in the deep earth environment and the engineering process that occurs during their operation.
  • Common deep ground structures can be deep ground repository, geothermal engineering, cave natural gas storage, etc.
  • deep earth environment refers to an environment with a depth of more than 100 meters above the ground.
  • the in-situ stress field and seepage field of deep structures have the following five characteristics at the same time: (1) The overburden pressure (axial pressure) of deep structures is relatively large, which can reach 20MPa at a depth of one thousand meters; (2) The confining pressure of deep structures is relatively large, reaching 20 MPa at a depth of one thousand meters; (3) For deep structures up to 100 meters, the weight stress and confining pressure change along the height of the deep structure, thus forming the weight stress Gradients and confining pressure gradients; (4) The stress field and seepage field of deep structures are coupled with each other, and the engineering process that occurs is very complicated. The changes in deformation, stress, saturation and other related parameters are difficult to describe by mathematical models and rely more on experiments.
  • in-situ refers to the measurement of a parameter without changing the original condition of the substance or isolating the substance from the original system.
  • Prototype refers to the physical object in the original system. In the present invention, it refers to the deep structure in the deep environment; model refers to the scale of the original system manufactured according to the similarity theory. Or the same size as the original system).
  • In-situ stress field and seepage field namely the prototype stress field and seepage field.
  • In-situ test refers to the test performed in-situ, such as setting up an instrument in an existing deep-seated repository for measurement.
  • the testers need to bring equipment to work in the deep environment.
  • part of the test subjects are national engineering equipment that is still in service. Therefore, in-situ testing lacks time flexibility and convenient operation Sex.
  • Physical simulation test refers to a physical simulation test.
  • a 1m high model is used in the laboratory to replace a 100m high deep repository prototype, and a pressure device is used to apply pressure on its top, bottom and sides.
  • the physical simulation experiment is simply referred to as the simulation experiment.
  • the method of simulation test is to place the model in the test device, and apply force and/or pore water into the surface of the model through the test device, so that the model generates a stress field and/or seepage field. When the applied force and/or the pore water flow rate meets specific requirements, an in-situ stress field and/or seepage field can be generated.
  • the simulation of deep ground engineering usually adopts a model with a scale of less than 10m.
  • Other geotechnical engineering does not have the five characteristics of deep ground engineering at the same time, so the models used in other geotechnical engineering simulations do not have to meet the above five conditions at the same time.
  • the confining pressure of the model is usually formed by squeezing the model by surrounding the pressure liquid on the side of the model.
  • the confining pressure at the top of the model is the set pressure of the device, and the confining pressure at the bottom of the model is the top confining pressure and the pressure liquid in this model.
  • the sum of weight at the bottom because the density of the pressurized liquid is usually smaller than that of the rock, and the height of the model is small, the self-weight of the pressurized liquid at the bottom of the model is negligibly small, so that the confining pressure gradient similar to the prototype cannot be formed.
  • the self-weight stress of the model is related to the scale of the model, but usually the model scale of the simulation test is less than 10 meters, so the difference between the self-weight stress at the top and the bottom is only 1/10 of the prototype.
  • the simulation of the seepage field is usually formed by injecting pore water into the model. Since the stress field of the model is different from the prototype, the resulting seepage field is also different from the prototype. In summary, the simulation test of deep ground engineering cannot restore the original seepage field and stress field.
  • the stress field is a general description of the instantaneous stress state of all points in the object.
  • the stress state refers to the stress of a certain point in an object in all possible directions. Stress refers to the internal force that generates interaction between various parts of the object when the object is deformed due to external factors (force, humidity, temperature field changes, etc.). The role of stress is to resist the action of this external cause and try to restore the object from its deformed position to its pre-deformed position.
  • the seepage field is a general description of the fluid pressure at all points inside the rock and soil. Seepage refers to the flow of pore water in a medium. In continuous rock and soil, seepage occurs when two points have different pore water pressures. In deep ground engineering, the common form of seepage is the flow of groundwater in rocks or deep ground engineering structures or between the two. Porewater pressure refers to the pressure generated by pore water. Porewater refers to the liquid present in the pores of rock and soil, usually water, but also other liquids.
  • overburden pressure refers to the pressure caused by the weight of the rock and soil over the research object, the direction is vertical downward, and the value increases linearly with depth.
  • Axial pressure refers to the direction perpendicular to the cross section and point to the inside of the pressure.
  • the axial pressure of deep ground engineering refers to the pressure of the overburden on the top and bottom of the model.
  • confining pressure refers to the pressure exerted by the surrounding rock mass on the research object in the rock and soil. The direction is horizontal and the vertical contact surface points into the object.
  • the confining pressure in the deep environment is mainly caused by the pressure of the overburden. It is generally considered that its value is equal to the pressure of the overburden and increases linearly with depth.
  • the self-weight stress refers to the stress caused by its own weight in the rock and soil.
  • the vertical self-weight stress at any point in the rock and soil mass is equal to the mass of the rock and soil column per unit area above this point.
  • the prototype is a rock with a height of 100m at a depth of 1000m, and the weight of the surrounding rock and rock is 25kN/m3.
  • the pressure in all directions is shown in Figure 1: the top axial pressure is 25MPa, the bottom axial pressure is 27.5MPa, the top confining pressure is 25MPa, the bottom confining pressure is 27.5MPa, the gap between the top and bottom of the dead weight stress is 2.5MPa, fluid pressure It is related to the flow and distribution of groundwater.
  • the model is a rock with a height of 1m, and the weight is 25kN/m3.
  • the top axial pressure is 25MPa and the top confining pressure is 25MPa.
  • the pressure liquid of the confining pressure is oil, and the weight is 8kN/m3.
  • the axial pressure at the bottom of the model is the sum of the top axial pressure and the gravity of the model, which is 25.025MPa
  • the confining pressure at the bottom is the sum of the top confining pressure and the oil gravity, which is 25.008MPa.
  • the gap between the top and bottom of the model's deadweight stress is 0.025MPa. Obviously, the stress field of the model is quite different from the prototype.
  • the purpose of the present invention is to provide a deep engineering in-situ stress field and seepage field supergravity simulation system, which can simulate In the test, high confining pressure and high stress are provided at the same time, and the in-situ confining pressure and self-weight stress gradient can be simulated to truly restore the in-situ stress field and seepage field of deep structures, so that the test results can reflect the prototype more reliably and accurately behaveing.
  • a super-gravity simulation system for in-situ stress field and seepage field of deep ground engineering including:
  • the triaxial pressure chamber is used to place the model and provide the in-situ axial pressure, confining pressure and seepage field of deep structures;
  • the analog control device is used to provide pressure liquid and pore water to the triaxial pressure chamber to generate the aforementioned axial pressure, confining pressure and seepage field, and can independently and accurately control the magnitude of the axial pressure, confining pressure and seepage field; signal; Acquisition device, used to monitor model deformation and seepage process during the test;
  • the three-axis pressure chamber is placed on a supergravity centrifuge, and the centrifugal acceleration generated by the supergravity centrifuge is n times the gravitational acceleration g (n is an integer greater than 1) to make the model in supergravity status.
  • n is an integer greater than or equal to 100.
  • the ultragravity centrifuge rotates at a constant angular velocity ⁇ , and the centrifugal acceleration provided is equal to r motion 2 (r is the distance between any point in the model and the center of rotation).
  • r the distance between any point in the model and the center of rotation.
  • the stress field of the model is the in-situ stress field.
  • the stress level at a depth of 1m in the model is the same as the stress field at 10m in the prototype
  • the stress level at 1 meter is the same as the stress field at 100 meters in the prototype.
  • the triaxial pressure chamber includes four channels, which are respectively an axial pressure channel, a confining pressure channel, a pore water inlet channel and a pore water outlet channel.
  • the analog control device includes a main control unit, a pressure percolation control unit, a data feedback unit and a source sink unit.
  • the axial pressure control unit is connected with the axial pressure channel for controlling the axial pressure in the triaxial pressure chamber;
  • the confining pressure control unit is connected with the confining pressure channel for controlling the confining pressure in the triaxial pressure chamber
  • the pore water inlet control unit is connected with the pore water inlet channel, and the pore water outlet control unit is connected with the pore water outlet channel. The two constitute the pressure difference between the pore water at the inlet and outlet and are used to control the seepage field in the triaxial pressure chamber .
  • the data feedback unit is used to collect axial pressure, confining pressure, and pore pressure in the three-axis pressure chamber during the simulation process, and transmit the collected data to the main control unit.
  • the source and sink unit is used to provide pressure liquid and/or pore water to the pressure seepage control unit.
  • the pressure seepage control unit includes a pressure seepage controller and a pressure seepage regulator; after receiving the pressure liquid or pore water output from the source and sink unit, the pressure seepage regulator monitors the flow rate of the pressure liquid and outputs it to the main controller Unit, and according to the feedback of the main control unit, dynamically adjust the pressure seepage controller output pressure liquid flow.
  • the pressure seepage controller includes a driving component, a liquid storage component, a control component, and an output component, and the driving component is used to convert the thrust of the pressure liquid output by the source and sink unit to its own thrust to the liquid storage component
  • the liquid storage component is a container for storing pressurized liquid or pore water.
  • the liquid in the container is not connected to the liquid output by the source and sink unit.
  • the liquid storage component is transported to the output component through a pipeline after being pushed by the driving component.
  • the control component is connected to the pressure regulator for controlling the flow of the liquid input to the drive component, and the output component is connected to the liquid storage component for outputting the pressure liquid or pore water in the liquid storage component to the three In the shaft pressure chamber.
  • the signal acquisition device includes sensors such as displacement, deformation, humidity, etc., for monitoring the deformation and seepage process of the sample during the test.
  • the triaxial pressure chamber further includes an axial pressure simulation component, a confining pressure simulation component and a seepage simulation component.
  • the axial pressure simulation component is connected to the axial pressure channel, and it includes a pair of axial pressure heads located at the top and bottom of the three-axis pressure chamber model. One of the pressure heads is fixed, and the other can move up and down. Axial pressure is applied to the model while being driven.
  • the confining pressure simulation component is connected to the confining pressure channel, and the pressure liquid output from the channel is guided into the triaxial pressure chamber, and the surrounding pressure is generated by the liquid surrounding the model.
  • the seepage simulation component is connected to the pore water inlet channel and the pore water outlet channel, and guides the pore water output from the pore water inlet channel to enter the porous plate at one end of the model, and then enter the model, and then from the other end of the model
  • the contacted porous plate flows out and flows into the pore water outlet channel, so that the model generates an in-situ pore water pressure difference, thereby forming an in-situ seepage field.
  • the perforated plate is a waterproof plate with the same shape as the bottom of the model, with circular holes arranged thereon, the distribution density of the holes is greater than or equal to 30, and the model and the perforated plate are wrapped with an impervious rubber film So that the two are in the same closed cavity, the impermeable rubber mold has only pore water inlet and outlet so that the pore water forms a seepage field inside the mold.
  • the present invention has the following beneficial effects:
  • This test device can simulate the gravity stress field gradient and the confining pressure gradient through the ultragravity centrifuge, and at the same time, simulate the confining pressure, axial pressure and pore water flow through the pressure seepage control unit, which can ensure that the stress field and seepage field of the model are in-situ stress Field and seepage field, improve the similarity, reliability and accuracy of simulation test.
  • the number of pressure seepage control units in the test device is four, namely the axial pressure control unit, the confining pressure control unit, the pore water inlet control unit, and the pore water outlet control unit; each unit includes a pressure seepage controller and a pressure seepage adjustment
  • the device can receive the pressure feedback from the main control unit to adjust the output pressure of the pressure seepage controller. It can output the pressure with an accuracy of 1% or form a pore water pressure difference with an accuracy of 1% to the triaxial pressure chamber through the command of the control unit .
  • Figure 1 is the force analysis diagram of the rock prototype in deep ground engineering.
  • Figure 2 is the force analysis diagram of the model in the simulation test under normal gravity
  • FIG. 3 is an overall schematic diagram of Embodiment 1 of the present invention.
  • Figure 4 is a control principle diagram of the first embodiment of the present invention.
  • FIG. 5 is a schematic diagram of the structure of the triaxial pressure chamber in the first embodiment of the present invention.
  • a deep geological disposal refers to a device that stores high-level radioactive waste underground at a distance of 500 m to 1000 m from the ground.
  • High-level radioactive waste the full name of high-level radioactive waste, or HLW in English, refers to radioactive waste that has a high content or concentration of radionuclides, a large amount of heat, and requires special shielding during operation and transportation.
  • the basic principle of the deep disposal of high-level radioactive waste is to build a repository for storing nuclear waste hundreds of meters underground.
  • the multiple barrier system formed by engineering barriers and geological barriers ensures that nuclear waste is not available for tens of thousands or even millions of years. Will cause harm to the surface biosphere.
  • the high-emission waste is sealed in a metal disposal tank.
  • the metal disposal tank is placed in the repository, and the space between the disposal tank and the surrounding rock is filled with buffer materials.
  • the buffer material is generally made of high-pressure bentonite, which expands when it meets water, which can support the surrounding rock. At the same time, bentonite also has a good blocking effect on the nuclide.
  • Buried high-level radioactive waste in a deep repository can be permanently isolated from the human living environment.
  • the specific method for the disposal of high-level waste in the deep repository is to process the high-level waste into a glass solidified body and seal it in a metal packaging container.
  • a metal packaging container is called a disposal tank.
  • a repository contains multiple disposal tanks. Before constructing the repository, it is necessary to dig a cave in the deep rock mass, fill the cave with a buffer barrier, and build the repository in the buffer barrier.
  • the surrounding rocks of the repository include mound rock, clay rock, tuff and rock salt, etc.
  • the wastes to be disposed of are high-level radioactive waste vitreous solidification, spent fuel and ⁇ waste.
  • Deep geological disposal of radioactive waste is a complex system engineering. Technically, it includes site selection and site evaluation, construction of underground laboratories, and the design, construction, operation and closure of repositories. It is considered that deep geological disposal is the most realistic and feasible method for the safe disposal of high-level radioactive
  • the glass solidified body, metal packaging container, buffer barrier and surrounding rock together constitute the near field of the deep repository.
  • the multi-field interaction of water and force in the near field of the deep repository can last for hundreds or even thousands of years.
  • the hydraulic-mechanical multi-field interaction refers to the coupling of the seepage process and the deformation process. This is because the deformation will change the void ratio of the material, which will cause the change of the permeability coefficient; and the seepage will change the saturation of the material, which will cause the change of the strength parameter.
  • the repository is usually located in a saturated zone of groundwater. In the initial stage after the closure of the repository, its interior is in an unsaturated state, and groundwater will gradually infiltrate to re-saturate it.
  • This process is called resaturation.
  • the high-level radioactive waste in the disposal tank will continue to release heat due to the decay reaction, and the accumulation of heat will increase the temperature of the disposal tank's surface.
  • the multi-physical process interactions of heat conduction, groundwater seepage, water vapor migration, buffer material expansion and surrounding rock deformation occur simultaneously in the repository.
  • the engineering characteristics of the buffer material and surrounding rock will change due to changes in stress, pore pressure, saturation and temperature, which will further affect the resaturation process.
  • the re-saturated state directly affects the source strength and boundary conditions of the nuclide migration in the near and far fields; on the other hand, the near-field seepage,
  • the mechanics and solute migration characteristics have an important impact on the safety evaluation of the repository. Therefore, it is particularly important to study the resaturation process in the near field of the repository on a hundred-year scale.
  • a deep engineering in-situ stress field and seepage field supergravity simulation system of this embodiment includes a supergravity centrifuge 1 for generating centrifugal acceleration, and three-axis pressure for placing the model Chamber 2, a signal acquisition device 206 for monitoring model deformation and seepage process during the test, and for supplying pressure liquid and pore water to the triaxial pressure chamber to generate the aforementioned axial pressure, confining pressure and seepage field, and to control the axis
  • the centrifugal acceleration that the ultragravity centrifuge can produce is n times the acceleration of gravity, and n is greater than 1, to generate supergravity acceleration, usually n is greater than or equal to 100,
  • the three-axis pressure chamber 2 is provided with four channels, and the four channels of the three-axis pressure chamber are the axial pressure channel 2013, the confining pressure channel 2021, the pore water inlet channel 20
  • the simulation control device includes a main control unit 5, a pressure seepage control unit, a data feedback unit 7 and a source and sink unit 8.
  • the pressure seepage control unit 6 is four, namely an axial pressure control unit 601 and a confining pressure control unit 603 , Pore water inlet control unit 603 and pore water outlet control unit 604;
  • the axial pressure control unit 601 is connected to the axial pressure channel 2013, and is used to control the axial pressure in the triaxial pressure chamber 2;
  • the confining pressure control unit 603 corresponds to The confining pressure channel 2021 is used to control the confining pressure in the triaxial pressure chamber 2;
  • the pore water inlet control unit 603 corresponds to the pore water inlet channel 2031, and the pore water outlet control unit 604 corresponds to the pore water outlet channel 2032, both of which constitute a pore
  • the pressure difference between the inlet and outlet of the water is used to control the seepage field in the triaxial pressure chamber 2;
  • the data feedback unit 7
  • the ultragravity centrifuge 1 includes a rotating arm and a hanging basket, and the three-axis pressure chamber 2 is placed on the hanging basket.
  • the simulation control device includes a main control unit 5, a pressure seepage control unit 6, There are four data feedback unit 7 and source sink unit 8; pressure and seepage control 6 units have four, namely axial pressure control unit 601, confining pressure control unit 602, pore water inlet control unit 603 and pore water outlet control unit 604.
  • the model 10 for simulating the deep underground repository is placed in the triaxial pressure chamber 2; the source and sink unit 8 is connected to the triaxial pressure chamber 2 through the pipeline 9 and the pressure seepage control unit 6; the pressure seepage control unit 6 and data feedback
  • the units 7 are all connected to the main control unit 5 and the triaxial pressure chamber 2.
  • the triaxial pressure chamber 2 and the pressure seepage control unit 6 are placed in the hanging basket; the data feedback unit 7 and the main control unit 5 are placed in the center of the boom;
  • the unit 8 is placed outside the ultra-heavy centrifuge 1.
  • the pressure seepage control unit 6 includes a pressure seepage controller and a pressure seepage regulator, more specifically, includes an axial pressure controller 6011, an axial pressure regulator 6012, and a confining pressure controller 6021 Confining pressure regulator 6022, pore water inlet controller 6031, pore water inlet regulator 6032, pore water outlet controller 6041, pore water outlet regulator 6042.
  • the axial pressure controller 6011, the confining pressure controller 6021, the pore water inlet controller 6031, and the pore water outlet controller 6041 are collectively referred to as pressure seepage controllers.
  • Axial pressure regulator 6012, confining pressure regulator 6022, pore water inlet regulator 6032, pore water outlet regulator 6042 are collectively referred to as pressure seepage regulators.
  • the pressure percolation regulator adjusts the output pressure or pore water flow rate of the pressure percolation controller according to the received pressure feedback signal output by the main control unit 5.
  • the pressure percolation controller includes a driving component, a liquid storage component, a control component, and an output component.
  • the driving component is used to convert the thrust of the pressure liquid output by the source sink unit 8 to its own storage.
  • the liquid storage component is a container for storing pressure liquid or pore water. The liquid in the container is not connected to the liquid output by the source and sink unit 8.
  • the liquid storage component passes through the pipeline after being pushed by the driving component.
  • the liquid is delivered to the output assembly, the control assembly is connected with a pressure regulator, and is used to control the flow of the liquid input to the drive assembly, and the output assembly is connected with the liquid storage assembly for connecting the pressure liquid or The pore water is output to the triaxial pressure chamber 2.
  • the pressure seepage regulator has a dynamic adjustment function. After receiving the pressure liquid or pore water output from the source and sink unit 8, it can dynamically adjust the input pressure seepage controller output according to the pressure fed back by the main control unit 5. The flow of liquid.
  • the three-axis pressure chamber 2 further includes an axial pressure simulation component, a confining pressure simulation component, and a seepage simulation component.
  • the axial pressure simulation component is a pair of shafts located at the top and bottom of the three-axis pressure chamber model.
  • the lower indenter 2012 in which the upper indenter 2011 is fixed, the lower indenter 2012 can move up and down and is connected with the axial compression channel 2013, and is connected with the axial compression channel 2013, the lower indenter 2012 is driven by the pressure liquid to apply the axis to the model 10
  • the confining pressure simulation component is connected to the confining pressure channel 2021, the pressure liquid output from the channel is guided into the cavity of the triaxial pressure chamber 2, and the surrounding pressure is generated by the liquid surrounding the model 10; the seepage simulation component and the pore
  • the water inlet channel 2031 and the pore water outlet channel 2032 are connected to guide the pressure liquid output from the pore water inlet channel 2031 into the porous plate 204 at the bottom of the model 10 and then into the model 10, and then through the porous plate 205 on the top of the model 10 from the pore water outlet channel
  • the flow of 2032 causes the top and bottom surfaces of the model 10 to produce the same seepage boundary as the actual situation, thereby forming the same seepage field as the actual situation
  • the bottom porous plate 204 and the top porous plate 205 are waterproof plates with the same radius as the model radius, and circular holes are uniformly distributed on them, and the number of holes is 30.
  • the triaxial pressure chamber 2 is a high-strength alloy steel cylindrical triaxial pressure chamber with a pressure range of 10-50MPa.
  • the cavity size is greater than 200mmX200mm.
  • the strength experience can be calculated to work normally within the centrifugal acceleration range of 50-300g.
  • the triaxial pressure chamber 2 is equipped with a deep reservoir model 10; the cavity of the triaxial pressure chamber 2 is provided with a porous plate 205 at the top, which is connected to the pore water outlet channel 2032, and the bottom is provided with a porous plate 204, which is connected to the pore water inlet channel 2031 ;
  • the outer bottom of the triaxial pressure chamber 2 is provided with an axial pressure channel 2013 and a confining pressure channel 2021; the triaxial pressure chamber 2 is provided with an upper pressure head 2011 and a lower pressure head 2012.
  • the pore water is injected through the pore water inlet channel 2031 and the pore water outlet channel 2032 to simulate the formed seepage field;
  • the pressure liquid is injected through the axial pressure channel 2013, and the lower head 2012 is in the pressure liquid Move up and squeeze the model 10 under the action of, to simulate the axial pressure; inject pressure liquid through the confining pressure channel 2021, and the pressure liquid surrounds and squeezes the model 10 to simulate the confining pressure;
  • a signal acquisition device 206 is installed in the triaxial pressure chamber, which specifically includes sensors such as displacement, deformation, and humidity, to monitor the deformation and seepage process of the sample during the test; the signal acquisition device 206 is placed in the triaxial pressure chamber 2 and passes The sensor channel 2061 transmits data to a processor outside the system.
  • the pressure control module of the present invention servo-controls the axial pressure of 25MPa, the confining pressure of 25MPa, and the pore water pressure of 10MPa to simulate the actual vertical and horizontal stress field and seepage field of the deep environment.
  • the simulation system of the present invention relies on the supergravity field generated by the supergravity centrifuge, and uses the pressure seepage control unit to make the device in the centrifuge simulate the multi-field interaction process of deep engineering; the supergravity field generated by the supergravity centrifuge is compensated for scale
  • the self-weight loss caused by the effect the simulated prototype has a self-weight stress field; further, because the distance from each point on the model to the centrifuge shaft is different, under the ng centrifugal acceleration based on the bottom of the model, if the distance from the bottom of the model to the centrifuge shaft is Is R, the distance from the top of the model to the centrifuge shaft is r, then the angular velocity of the centrifuge rotation can be calculated as ng/R2, and the centrifugal acceleration at the top of the model is ngr2/R2.
  • the system simulates The self-weight stress gradient of ⁇ is the self 2 simulated by the system; the control unit applies axial compression to the model to simulate the vertical stress field of the prototype; the control unit applies confining pressure to the model to simulate the horizontal stress field of the prototype; seepage control unit pairs the model Pore pressure is applied to simulate the seepage process of the prototype; the time-lapse effect of the centrifuge reproduces the long-term (thousand or even ten thousand years) stress field and seepage field changes of the prototype.
  • the scale effect of the centrifuge means that under the centrifugal acceleration of ng, the size of the model used in the test is 1/n of the prototype;
  • the time-lapse effect of the centrifuge means that the model used in the test is under the centrifugal acceleration of ng
  • the time taken is 1/n of the prototype process.
  • the data feedback unit 7 in the analog control device is used to monitor the pressure liquid and pore water input into the triaxial pressure chamber 2 in real time.
  • the flow rate is fed back to the main control unit 5 in real time; the flow rate of the pressure liquid and pore water input from the source sink unit 8 is monitored through the pressure seepage control unit in the analog control device, and fed back to the main control unit 5 in real time.
  • the command issued by unit 5 regulates the input and output liquid flow.
  • the data of the signal acquisition device 206 is output to a processor outside the system.
  • the signal acquisition device 206 After reaching the centrifugal acceleration required for the test, the signal acquisition device 206 starts to perform long-term pressure, displacement and seepage monitoring.
  • the output control accuracy of axial pressure, confining pressure, and pore water pressure difference reached 1% after the measurement of pressure and flow sensors were compared with the preset pressure and flow values of the host.

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Abstract

本发明公开了一种深地工程原位应力场和渗流场超重力模拟系统，包括：三轴压力室，用于放置模型，并提供深地构筑物的原位轴压、围压以及所处的渗流场；模拟控制装置，用于向三轴压力室提供压力液体和孔隙水以产生前述轴压、围压和渗流场，并控制轴压、围压和渗流场的量值；信号采集装置，用于在试验过程中监测模型变形和渗流过程。本发明提高了模拟试验的相似性、可靠型和准确性，且可以通过控制单元的指令向三轴压力室输出精度达1％的压力或构成精度达1％的孔隙水压力差。

Description

一种深地工程原位应力场和渗流场超重力模拟系统 技术领域
本发明涉及一种岩土工程领域物理模拟试验系统，具体涉及一种深地工程原位应力场和渗流场超重力模拟系统。
背景技术
深地工程(deep earth engineering)，指在深地环境中的深地构筑物建造过程和其运行过程中发生的的工程过程。常见的深地构筑物可以是深地处置库、地热工程、岩穴天然气储库等。
其中，深地环境(deep earth environment)，指距地表百米级深度以上的环境。
深地构筑物原位应力场和渗流场同时具备以下五个特点：(1)深地构筑物受到的上覆岩层压力(轴压)较大，在千米级的深度下可达到20MPa；(2)深地构筑物受到的围压较大，在千米级的深度下可达到20MPa；(3)深地构筑物达百米尺度，自重应力和围压沿深地构筑物高度方向变化，从而形成了自重应力梯度和围压梯度；(4)深地构筑物的应力场和渗流场互相耦合，其中发生的工程过程十分复杂，形变、应力、饱和度等相关参数的变化难以用数学模型描述，更依赖于试验得出；(5)应力场和渗流场的变化是漫长的，上述的参数变化要百年乃至千年才会稳定。其中，原位(in-situ)指的是在测量某个参数时，并没有改变物质的原始条件或把物质从原来的系统中隔离出来。原型(prototype)指的是原系统中的实物，本发明中是指深地环境中的深地构筑物；模型(model)指的是根据相似性理论制造的按原系统比例缩小(也可以是放大或与原系统尺寸一样)的实物。原位应力场和渗流场，即原型的应力场和渗流场。
其他的岩土工程的研究对象不同时具备上述五个特点，与深地工程有本质上的区别。
为测定深地工程中形变、应力、饱和度等相关参数的变化，需进行试验。试验分原位试验和模拟试验。原位试验指在原位进行的试验，如在现存的深地处置库中架设仪器进行测量。进行深地工程原位试验时，一方面需要试验人员携带设备进入深地环境中工作，另一方面部分实验对象是仍在服役的国家工程设备，因此，原位测试缺乏时间灵活性和操作方便性。此外，如前述的深地工程的应力场和渗流场的特点(5)，对参数变化的完整测定需要百年乃至千年尺度的试验时间，远大于一般意义下社会或技术活动所涉及的时间尺度。
因此，在实验室内进行的物理模拟试验为更优选。物理模拟试验指模型是实物的模拟试验，如在实验室中用1m高的模型来代替100m高的深地处置库原型，并用压力装置在其顶、底面和侧面加压力的试验。以下将物理模拟实验简称为模拟试验。模拟试验的方法是，将模型放置在试验装置内，并通过试验装置在模型的表面施加力和/或通入孔隙水，使模型产生应力场和/或渗流场。当施加的力和/或通入孔隙水流量达到特定要求时，可以产生原位应力场和/或渗流场。考虑到实验室场地大小限制，对深地工程的模拟通常采用10m以下尺度的模型。其他的岩土工程不同时具备深地工程的五个特点，因此其他岩土工程进行模拟时所用的模型，也不必同时满足上述五个条件。
如前所述，模拟试验中，模型上下底面的轴压是确定值，易于施加。模型的围压的施加方式通常是通过模型侧面环绕压力液体对模型进行挤压来形成，模型顶部的围压为装置的设定压力，模型底部的围压为顶部围压与压力液体在此模型底部的自重之和。由于压力液体的密度通常小于岩石，且模型高度较小，压力液体在模型底部的自重小到可以忽略不计，这样无法形成和原型相似的围压梯度。模型的自重应力与模型的尺度有关，但通常模拟试验的模型尺度在10米以下，因此自重应力在顶部与底部的差距仅为原型的1/10。渗流场的模拟通常通过在模型内部注入孔隙水形成。由于模型的应力场与原型不同，导致的渗流场也与原型不同。综上所述，深地工程的模拟试验，无法还原原位的渗流场与应力场。
其中，应力场(stress field)是对物体中所有点的瞬时应力状态的总体描述。应力状态(stressstate)是指物体中的某一点在所有可能方向上的应力。应力(stress)是指物体由于外因(受力、湿度、温度场变化等)而变形时，在物体内各部分之间产生相互作用的内力。应力的作用是抵抗这种外因的作用，并试图使物体从变形后的位置恢复到变形前的位置。
其中，渗流场(seepage field)是对岩土体内部所有点的流体压力情况的总体描述。渗流(seepage) 是指孔隙水在介质中的流动。在连续岩土体中，当两点具有不同的孔隙水压力时，会发生渗流。在深地工程中，渗流的常见形式是地下水在岩石或深地工程构筑物中的流动或两者之间的流动。孔隙水压力(porewaterpressure)指孔隙水产生的压力。孔隙水(porewater)是指存在于岩土体孔隙中的液体，通常为水，也可为其他液体。
其中，上覆岩层压力(overburdenpressure)，指覆盖在研究对象以上的岩土体的重量造成的压力，方向竖直向下，数值随着深度而线性增加。轴压(axialpressure)指方向垂直于截面并指向截面内部的压力。在模拟试验系统中，深地工程的轴压指的是模型顶面和底面的上覆岩层压力。
其中，围压(confiningpressure)指周围岩体对岩土体内的研究对象施加的压力，方向水平并垂直接触面指向对象内。在深地环境中的围压，主要是由上覆岩层压力所致，通常认为其数值与上覆岩层压力相等，随着深度而线性增加。
其中，自重应力(geostatic stress/self-weight stress)是指岩土体内由自身重量引起的应力。岩土体中任一点垂直方向的自重应力，等于这一点以上单位面积岩土柱的质量。
为了更具体地说明差异，以一组原型和模型的应力场模拟情况为例。原型为1000m深度下的高100m的岩石，围岩及岩石的重度取25kN/m3。其所受各向压力图1所示：顶部轴压为25MPa，底部轴压为27.5MPa，顶部围压为25MPa，底部围压为27.5MPa，自重应力顶部与底部的差距为2.5MPa，流体压力与地下水的流动和分布情况有关。模型为高1m的岩石，重度取25kN/m3。对其施加顶部轴压25MPa，顶部围压25MPa，围压的压力液体为油，重度为8kN/m3。其所受各向压力图2所示，模型底部的轴压为顶部轴压与模型重力之和，为25.025MPa，底部的围压为顶部围压与油重力之和，为25.008MPa。模型的自重应力顶部与底部的差距0.025MPa。显然，模型的应力场与原型相差较大。
综上所述，深地工程的模拟试验虽然具有操作方便、时间安排灵活的优点，但是仍然具有模拟时间尺度有限以及无法完全还原围压梯度和自重应力梯度的缺点。在常重力下，没有办法很好地模拟深地工程的应力场和渗流场。
发明内容
为克服现有技术中模拟时间尺度有限及无法完全还原原位应力场和渗流场的不足，本发明的目的在于提供一种深地工程原位应力场和渗流场超重力模拟系统，能够在模拟试验中同时提供高围压和高应力，并能够模拟原位围压和自重应力梯度，以真实地还原深地构筑物的原位应力场和渗流场，使试验结果能够更可靠、准确地反映原型情况。
为实现上述目的，本发明所采用的技术方案是：
一种深地工程原位应力场和渗流场超重力模拟系统，包括：
三轴压力室，用于放置模型，并提供深地构筑物的原位轴压、围压以及所处的渗流场；
模拟控制装置，用于向三轴压力室提供压力液体和孔隙水以产生前述轴压、围压和渗流场，并能独立且高精度地控制轴压、围压和渗流场的量值；信号采集装置，用于在试验过程中监测模型变形和渗流过程；
进行模拟试验时，将所述三轴压力室放置在超重力离心机上，且该超重力离心机产生的离心加速度为重力加速度g的n倍(n为大于1的整数)以使模型处于超重力状态。
优选的，n取大于等于100的整数。
其中，超重力离心机以恒定的角速度ω转动，所提供的离心加速度等于r动2(r为模型中任意一点距转动中心的距离)。如果模型采用与原型相同的材料，那么当离心加速度为n倍的重力加速度时(ng＝r的2)，模型深度hm处研究对象将与原型hp＝nhm处的研究对象具有相同的竖向应力：σm＝σp。这就是超重力离心模拟最基本的相似比原理，即尺寸缩小n倍的模型承受n倍重力加速度时，模型的应力场为原位应力场。例如，当n＝10，也就是加速度为10g时，模型中深度为1米处的应力水平与原型中10米处的应力场相同；当n＝100，也就是加速度为100g时，模型中深度为1米处的应力水平与原型中100米处的应力场相同。
上述技术方案还可以通过以下技术措施进一步完善：
优选的，所述三轴压力室包括四个通道，该四个通道分别为轴压通道、围压通道、孔隙水进口通道和孔隙水出口通道。
优选的，所述模拟控制装置包括主控单元、压力渗流控制单元、数据反馈单元和源汇单元。所述压力渗流控制单元为四个，分别为轴压控制单元、围压控制单元、孔隙水进口控制单元和孔隙水出口控制单元。
优选的，所述轴压控制单元与轴压通道连接，用于控制三轴压力室中的轴压；所述围压控制单元与围压通道连接，用于控制三轴压力室中的围压；所述孔隙水进口控制单元与孔隙水进口通道连接，孔隙水出口控制单元与孔隙水出口通道连接，两者构成孔隙水在进出口的压力差，用于控制三轴压力室中的渗流场。
优选的，所述数据反馈单元用于采集模拟过程中三轴压力室内的轴压、围压、孔压，并将采集的数据传输给主控单元。
优选的，所述源汇单元用于向压力渗流控制单元提供压力液体和/或孔隙水。
优选的，所述压力渗流控制单元包括压力渗流控制器和压力渗流调节器；在接收从源汇单元输出的压力液体或孔隙水后，压力渗流调节器监测该压力液体的流量并输出给主控单元，且根据主控单元的反馈，动态调节压力渗流控制器输出压力液体的流量。
优选的，所述压力渗流控制器包括驱动组件、储液组件、控制组件和输出组件，所述驱动组件用于将源汇单元输出的压力液体对自身的推力转化为自身对储液组件的推力，所述储液组件为储存压力液体或孔隙水的容器，该容器中的液体与源汇单元输出的液体不连通，储液组件在受到驱动组件对自身的推力后通过管道向输出组件输送其中的液体，所述控制组件与压力调节器相连，用于控制输入驱动组件的液体的流量，所述输出组件与储液组件相连，用于将储液组件中的压力液体或孔隙水输出到三轴压力室中。
优选的，所述信号采集装置包含位移、变形、湿度等传感器，用于监测试验过程中试样的变形和渗流过程。
优选的，所述三轴压力室还包括轴压模拟组件、围压模拟组件和渗流模拟组件。所述轴压模拟组件与轴压通道相连，其包括一对位于三轴压力室内模型的顶部和底部的轴压压头，其中一压头固定，另一压头可上下移动，在压力液体的驱动下对模型施加轴向压力。
优选的，所述围压模拟组件与围压通道相连，引导通道中输出的压力液体进入三轴压力室内，通过围绕模型的液体对其产生周围压力。
优选的，所述渗流模拟组件与孔隙水进口通道和孔隙水出口通道相连，引导孔隙水进口通道中输出的孔隙水进入位于模型某一端所接触的多孔板后进入模型内部，再从模型另一端所接触的多孔板流出，流进孔隙水出口通道，使模型产生原位孔隙水压力差，从而形成原位渗流场。
优选的，所述多孔板为与模型的底部形状相同且防水的板材，其上布置圆形孔洞，孔洞的分布密度大于等于30个，且所述模型和多孔板的外侧包裹有一不透水橡胶膜以使二者处在同一封闭空腔内，所述不透水橡胶模上仅具有孔隙水进口和出口以使孔隙水在模型内部形成渗流场。
由于采用了以上技术措施，本发明具有的有益效果是：
本试验装置能够通过超重力离心机模拟自重应力场梯度和围压梯度，同时，通过压力渗流控制单元模拟围压、轴压和孔隙水流量，能够保证模型的应力场和渗流场为原位应力场和渗流场，提高模拟试验的相似性、可靠型和准确性。
试验装置中的压力渗流控制单元个数为四个，分别为轴压控制单元、围压控制单元、孔隙水进口控制单元、孔隙水出口控制单元；每个单元包括压力渗流控制器和压力渗流调节器，能够接收主控单元反馈的压力，从而调节压力渗流控制器的输出压力，可以通过控制单元的指令向三轴压力室输出精度达1％的压力或构成精度达1％的孔隙水压力差。
附图说明
图1是深地工程中岩石原型的受力分析图。
图2是在常重力下模拟试验中的模型受力分析图；
图3是本发明实施例一的整体示意图；
图4是本发明实施例一的控制原理图；
图5是本发明实施例一的三轴压力室的结构示意图；
图中：1-超重力离心机；2-三轴压力室；2011-上压头；2012-下压头；2013-轴压通道；2021-围压通道；2031-孔隙水进口通道；2032-孔隙水出口通道；204-顶部多孔板；205-底部多孔板；206-信号采集装置；2061- 信号采集通道；5-主控单元；601-轴压控制单元；6011-轴压控制器；6012-轴压调节器；602-围压控制单元；6021-围压控制器；6022-围压调节器；603-孔隙水进口控制单元；6031-孔隙水进口控制器；6032-孔隙水进口调节器；604-孔隙水出口控制单元；6041-孔隙水出口控制器；6042-孔隙水出口调节器；7-数据反馈单元；8-源汇单元；9-管路；10-模型。
具体实施方式
下面结合附图和实施例对本发明作进一步详细说明。以下实施例仅用于说明本发明而不用于限制本发明的范围。此外应理解，在阅读了本发明讲授的内容之后，本领域技术人员可以对本发明作各种改动或修改，这些等价形式同样落于本申请所附权利要求书所限定的范围。
下面以深地处置库为例，介绍本系统的必要性和优越性。
在本发明中，深地处置库(deep geological disposal)是指在距离地表500m至1000m的地下储存高放废物的装置。高放废物，全称高水平放射性废物(high level radioactive waste)，英文简称HLW，是指放射性核素的含量或浓度高，释热量大，操作和运输过程中需要特殊屏蔽的放射性废物。
高放废物深地处置的基本原理是在地下数百米处建设用于存放核废料处置库，通过工程屏障和地质屏障形成的多重屏障系统，确保核废料在数万甚至百万年时间内不会对地表生物圈产生危害。高射废物封存于金属处置罐中，将金属处置罐安置于处置库内，处置罐与围岩之间用缓冲材料进行填充。缓冲材料一般由高压实膨润土制成，其遇水后会发生膨胀，可以对围岩产生支撑，同时膨润土对核素也有较好的阻滞作用。
将高放废物埋藏在深地处置库中，可以做到永久与人类生存环境隔离。深地处置库处置高放废物的具体做法是：将高放废物加工处理成玻璃固化体，并将其密封在金属包装容器中，这样的金属包装容器称作处置罐。一个处置库中含有多个处置罐。建造处置库前需先在深部岩体中挖掘洞穴，并在洞穴内部填充缓冲屏障，在缓冲屏障中建造处置库。处置库围岩包括岗岩类、粘土岩、凝灰岩和岩盐等，被处置的废物为高放废物玻璃固化体、乏燃料和α废物等。对放射性废物进行深地质处置是一项复杂的系统工程。在技术上包括选址和场址评价、建造地下实验室及设计、建造、运行和关闭的处置库。被认为深地质处置是安全处置高放废物最现实可行的方法。
其中，玻璃固化体、金属包装容器、缓冲屏障及围岩等共同构成深地处置库的近场。深地处置库近场的水-力多场相互作用可持续上百年乃至上千年。水-力多场相互作用指渗流过程和变形过程耦合，这是因为变形会改变材料的孔隙比，从而引起渗透系数的改变；而渗流会改变材料的饱和度，从而引起强度参数的改变。处置库通常位于地下水饱和带。处置库封闭后初期，其内部处于非饱和状态，地下水将逐渐入渗，使其重新饱和，该过程称为再饱和。在再饱和过程的同时，处置罐中的高放射性废物由于衰变反应会持续释放热量，热量的积聚会使处置罐表面的温度上升。在处置库中同时发生着热传导、地下水渗流、水蒸气运移、缓冲材料膨胀及围岩变形的多物理过程相互作用。在此过程中，缓冲材料及围岩由于应力、孔压、饱和度及温度的变化，其工程特性会发生改变，从而进一步的对再饱和过程产生影响。
在高放射性废弃物深地处置工程中，当处置库再饱和后，地下水逐渐腐蚀金属处置罐，并最终进入处置罐中与核废料接触。此时，核废料中的核素溶解于地下水中向外迁移，并通过工程屏障和地质屏障进入地表生物圈。处置库封闭后再饱和过程所需的时间是处置库安全评价中必须回答的问题之一，这一过需要约百年时间。一方面，再饱和后的状态直接影响了核素在近场及远场中迁移时的源强和边界条件；另一方面，经过热-水-力共同作用后的处置库近场的渗流、力学及溶质迁移特性对处置库的安全评价产生重要的影响。因此，对处置库近场百年尺度的再饱和过程的研究就显得尤为重要。
实施例一：
如图2至4所示，本实施例的一种深地工程原位应力场和渗流场超重力模拟系统，包括用于产生离心加速度的超重力离心机1，用于放置模型的三轴压力室2，用于在试验过程中监测模型变形和渗流过程的信号采集装置206，以及用于向三轴压力室提供压力液体和孔隙水以产生前述轴压、围压和渗流场，并控制轴压、围压和渗流场的量值的模拟控制装置；所述超重力离心机可产生的离心加速度n倍于重力加速度，且n大于1，以产生超重力加速度，通常n大于或等于100，以产生超高重力加速度；所述三轴压力室2 内设置有四个通道，所述三轴压力室的四个通道分别为轴压通道2013、围压通道2021、孔隙水进口通道2031和孔隙水出口通道2032；该三轴压力室2为现有的三轴压力室。所述模拟控制装置包括主控单元5、压力渗流控制单元、数据反馈单元7和源汇单元8；所述压力渗流控制单元6为四个，分别为轴压控制单元601、围压控制单元603、孔隙水进口控制单元603和孔隙水出口控制单元604；所述轴压控制单元601与轴压通道2013连接，用于控制三轴压力室2中的轴压；所述围压控制单元603对应围压通道2021，用于控制三轴压力室2中的围压；所述孔隙水进口控制单元603对应孔隙水进口通道2031，孔隙水出口控制单元604对应孔隙水出口通道2032，两者构成孔隙水在进出口的压力差，用于控制三轴压力室2中的渗流场；所述数据反馈单元7用于采集模拟过程中从压力渗流控制单元输出至三轴压力室内的轴压、围压、孔隙水流量，并将采集的数据传输给主控单元5；所述源汇单元8用于向压力渗流控制单元6提供压力液体和/或孔隙水；所述模拟系统通过超重力离心机1的运行产生的超重力加速度模拟具有梯度的围压和自重应力场，通过压力渗流控制单元6模拟原型原位的渗流场。
在本实施例中，如图2所示，超重力离心机1包含转臂和吊篮，三轴压力室2放置在吊篮上，模拟控制装置包括主控单元5、压力渗流控制单元6、数据反馈单元7和源汇单元8；压力和渗流控制6单元有四个，分别为轴压压力控制单元601、围压压力控制单元602、孔隙水进口控制单元603和孔隙水出口控制单元604。用于模拟深地处置库的模型10置于三轴压力室2中；源汇单元8通过管路9、和压力渗流控制单元6连接到三轴压力室2；压力渗流控制单元6和数据反馈单元7均与主控单元5和三轴压力室2相连，三轴压力室2和压力渗流控制单元6置于吊篮内；数据反馈单元7和主控单元5置于转臂中心；源汇单元8置于超重离心机1外。
在本实施例中，所述压力渗流控制单元6包括压力渗流控制器和压力渗流调节器，更具体地，包括轴压压力控制器6011、轴压压力调节器6012，围压压力控制器6021、围压压力调节器6022，孔隙水进口控制器6031、孔隙水进口调节器6032,孔隙水出口控制器6041，孔隙水出口调节器6042。轴压压力控制器6011、围压压力控制器6021、孔隙水进口控制器6031、孔隙水出口控制器6041统称为压力渗流控制器。轴压压力调节器6012、围压压力调节器6022、孔隙水进口调节器6032、孔隙水出口调节器6042统称为压力渗流调节器。所述压力渗流调节器根据接收到的主控单元5输出的压力反馈信号，从而调节压力渗流控制器的输出压力或输出孔隙水流量。
在本实施例中，所述压力渗流控制器包括驱动组件、储液组件、控制组件和输出组件，所述驱动组件用于将源汇单元8输出的压力液体对自身的推力转化为自身对储液组件的推力，所述储液组件为储存压力液体或孔隙水的容器，该容器中的液体与源汇单元8输出的液体不连通，储液组件在受到驱动组件对自身的推力后通过管道向输出组件输送其中的液体，所述控制组件与压力调节器相连，用于控制输入驱动组件的液体的流量，所述输出组件与储液组件相连，用于将储液组件中的压力液体或孔隙水输出到三轴压力室2中。
在本实施例中，所述压力渗流调节器有动态调节功能，在接收从源汇单元8输出的压力液体或孔隙水后，能够根据主控单元5反馈的压力动态调节输入压力渗流控制器输出液体的流量。
在本实施例中，所述三轴压力室2还包括轴压模拟组件、围压模拟组件和渗流模拟组件，所述轴压模拟组件是一对位于三轴压力室内模型的顶部和底部的轴压压头，其中上压头2011固定，下压头2012可上下移动并与与轴压通道2013相连，并与轴压通道2013连接，下压头2012在压力液体的驱动下对模型10施加轴压；所述围压模拟组件与围压通道2021相连，引导通道中输出的压力液体进入三轴压力室2腔内，通过围绕模型10的液体对其产生周围压力；所述渗流模拟组件与孔隙水进口通道2031和孔隙水出口通道相连2032，引导孔隙水进口通道2031中输出的压力液体进入模型10底部的多孔板204后进入模型10，再经模型10顶部的多孔板205从孔隙水出口通道2032流出，使模型10的顶、底面产生与实际情况相同的渗流边界，从而形成和实际情况相同的渗流场。
在本实施例中，所述底部多孔板204和顶部多孔板205为半径与模型半径相同的防水板材，其上均布圆形孔洞，孔洞的数量为30个。
三轴压力室2是耐压范围为10～50MPa的高强度合金钢圆柱形三轴压力室，腔内尺寸大于200mmX200mm，强度经验算可以在离心加速度50～300g范围内正常工作。
三轴压力室2内置有深地处置库模型10；三轴压力室2腔内顶部设有多孔板205，与孔隙水出口通道 2032相连，底部设有多孔板204，与孔隙水进口通道2031相连；三轴压力室2外侧底部设有轴压通道2013和围压通道2021；三轴压力室2内设有上压头2011、下压头2012。
三轴压力室2内放入模型10后，通过孔隙水进口通道2031、孔隙水出口通道2032注入孔隙水，模拟形成的渗流场；通过轴压通道2013注入压力液体，下压头2012在压力液体的作用下向上移动并挤压模型10，模拟轴压；通过围压通道2021注入压力液体，压力液体环绕并挤压模型10，模拟围压；
在三轴压力室内设置信号采集装置206，具体包括位移、变形、湿度等传感器，用于监测试验过程中试样的变形和渗流过程；信号采集装置206置于三轴压力室2内，并通过传感器通道2061将数据传输至系统外的处理器上。
本发明的压力控制模块伺服控制压力轴压25MPa、围压25MPa、孔隙水压力10MPa，以模拟深地环境的实际竖向、水平应力场和渗流场。
本发明的模拟系统依靠超重力离心机产生的超重力场，并通过压力渗流控制单元使离心机内的装置模拟深地工程多场相互作用过程；超重力离心机产生的超重力场补偿缩尺效应带来的自重损失，模拟原型具有自重应力场；进一步地，由于模型上各点至离心机转轴的距离不同，在以模型底部为基准的ng离心加速度下，若模型底部至离心机转轴距离为R，模型顶部至离心机转轴距离为r，则可计算出离心机旋转的角速度为ng/R2，模型顶部的离心加速度为ngr2/R2，若该模型的容重为γ，则该系统所模拟的自重应力梯度为γ则该系统所模拟的自2；控制单元对模型施加轴压，模拟原型竖向应力场；控制单元对模型施加围压，模拟原型水平向应力场；渗流控制单元对模型施加孔压，模拟原型渗流过程；离心机的缩时效应，再现原型长期(千年甚至万年)的应力场、渗流场变化。其中，离心机的缩尺效应指的是，在ng的离心加速度下，试验所用模型尺寸为原型的1/n；离心机的缩时效应指的是，在ng的离心加速度下，试验所用模型发生的动态过程在达到与原型同样效果时，所用时间为原型过程历时的1/n。
本发明的具体工作过程如下：
将装有深地处置库及缓冲屏障、围岩模型10的三轴压力室2放置在超重力离心机1的吊篮上，将压力渗流控制装置6的相关管路9与三轴压力室2相连；通过源汇单元8向压力渗流控制装置6注入孔隙水和压力液体，将传感器通道2061与信号采集装置206连接。
设置完毕后，开启超重力离心机1，离心加速度从1g逐渐增加至100g，在加速过程中，通过模拟控制装置中的数据反馈单元7实时监测输入三轴压力室2的压力液体和孔隙水的流量，并实时反馈给主控单元5；通过模拟控制装置中的压力渗流控制单元时监测从源汇单元8输入的压力液体和孔隙水的流量，并实时反馈给主控单元5，根据主控单元5下达的命令调节输入和输出的液体流量。信号采集装置206的数据输出至系统外的处理器。
达到试验需要的离心加速度后信号采集装置206开始进行长期的压力、位移及渗流监测。
试验结束后，停机，逐渐降低离心加速度至1g，取出三轴压力室2处理模型10。系统外的处理器整理试验全过程中收集到的数据，进行后续分析。
在本实施例中，经压力、流量传感器的测定与主机预设压力、流量值对比，轴压、围压和孔隙水压力差的输出控制精度达到了1％。
本说明书列举的仅为本发明的较佳实施方式，凡在本发明的工作原理和思路下所做的等同技术交换，均视为本发明的保护范围。

Claims (15)

  1. 一种深地工程原位应力场和渗流场超重力模拟系统，包括：
    三轴压力室，用于放置模型，并提供深地构筑物的原位轴压、围压以及所处的渗流场；
    模拟控制装置，用于向三轴压力室提供压力液体和孔隙水以产生前述轴压、围压和渗流场，并控制轴压、围压和渗流场的量值；
    信号采集装置，用于在试验过程中监测模型变形和渗流过程；
    进行模拟试验时，将所述三轴压力室放置在超重力离心机上，且该超重力离心机产生的离心加速度为重力加速度g的n倍(n为大于1的整数)以使模型处于超重力状态，从而产生具有梯度的自重应力；使围压压力液体处于超重力状态，从而产生具有梯度的围压压力。
  2. 如权利要求1所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述三轴压力室包括四个通道，该四个通道分别为轴压通道、围压通道、孔隙水进口通道和孔隙水出口通道。
  3. 如权利要求1或2所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述模拟控制装置包括主控单元、压力渗流控制单元、数据反馈单元和源汇单元。
  4. 如权利要求2或3所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述压力渗流控制单元为四个，分别为轴压控制单元、围压控制单元、孔隙水进口控制单元和孔隙水出口控制单元，从而可以独立控制模型的轴压、围压和渗流场。
  5. 如权利要求4所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：
    所述轴压控制单元与轴压通道连接，用于控制三轴压力室中的轴压；
    所述围压控制单元与围压通道连接，用于控制三轴压力室中的围压；
    所述孔隙水进口控制单元与孔隙水进口通道连接，孔隙水出口控制单元与孔隙水出口通道连接，两者构成孔隙水在进出口的压力差，用于控制三轴压力室中的渗流场。
  6. 如权利要求2或3所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述数据反馈单元用于采集模拟过程中从压力渗流控制单元输出至三轴压力室内的轴压、围压、孔隙水流量，并将采集的数据传输给主控单元。
  7. 如权利要求3所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：
    所述源汇单元用于向压力渗流控制单元提供压力液体和/或孔隙水。
  8. 如权利要求7所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述压力渗流控制单元包括压力渗流控制器和压力渗流调节器；在接收从源汇单元输出的压力液体或孔隙水后，压力渗流调节器监测该液体的流量并输出给主控单元，且根据主控单元的反馈，动态调节压力渗流控制器输出液体的流量。
  9. 如权利要求8所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述压力渗流控制器包括驱动组件、储液组件、控制组件和输出组件，所述驱动组件用于将源汇单元输出的压力液体对自身的推力转化为自身对储液组件的推力，所述储液组件为储存压力液体或孔隙水的容器，该容器中的液体与源汇单元输出的液体不连通，储液组件在受到驱动组件对自身的推力后通过管道向输出组件输送其中的液体，所述控制组件与压力渗流调节器相连，用于控制输入驱动组件的液体的流量，所述输出组件与储液组件相连，用于将储液组件中的压力液体或孔隙水输出到三轴压力室中。
  10. 如权利要求1所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述信号采集装置包含位移、变形、湿度等传感器，用于监测试验过程中试样的变形和渗流过程。
  11. 如权利要求2所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述三轴压力室还包括轴压模拟组件、围压模拟组件和渗流模拟组件。
  12. 如权利要求11所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述轴压模拟组件与轴压通道相连，其包括一对位于三轴压力室内模型的顶部和底部的轴压压头，其中一压头固定，另一压头可上下移动，在压力液体的驱动下对模型施加轴向压力。
  13. 如权利要求11所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述围压模拟组件与围压通道相连，引导所述围压通道中输出的压力液体进入三轴压力室内，通过围绕模型的液体对其产生周围压力。
  14. 如权利要求11所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述渗流模拟组件与孔隙水进口通道和孔隙水出口通道相连，引导孔隙水进口通道中输出的孔隙水进入位于模型某一端所接触的多孔板后进入模型内部，再从模型另一端所接触的多孔板流出，流进孔隙水出口通道，使模型产生原位孔隙水压力差，从而形成原位渗流场。
  15. 如权利要求14所述深地工程原位应力场和渗流场超重力模拟系统，其特征在于：所述多孔板为与模型的底部形状相同且防水的板材，其上布置圆形孔洞，孔洞的分布密度大于等于30个，且所述模型和多孔板的外侧包裹有一不透水橡胶膜以使二者处在同一封闭空腔内，所述不透水橡胶模上仅具有孔隙水 进口和出口以使孔隙水在模型内部形成渗流场。
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