多功能真三轴流固耦合试验系统的研制与应用

发布时间：2018-08-11 14:08

【摘要】：为了更真实地模拟地下煤岩体所处的三向不等主应力状态,同时揭示真三轴流固耦合条件下煤岩的力学特性与流体在其中的渗流规律,自行研制多功能真三轴流固耦合试验系统,该系统主要由框架式机架、真三轴压力室、加载系统、内密封渗流系统、控制和数据测量、采集系统及声发射监测系统组成。该系统的先进性和创新性如下:(1)可实现多种复杂应力路径下单轴、双轴、真三轴应力状态下煤岩力学特性与流体渗流规律研究;(2)为了实现多轴联动保证试件中心点不变,设计3种新的加卸载控制方式(追踪力Trace-F、追踪位移Trace-D、追踪位移修正Trace-Df);(3)特殊设计的内密封渗流系统配合伺服增压系统,首次实现了真三轴应力条件下气液的自由渗流控制与监测;(4)试验系统采取两向刚性+一向柔性或刚性加载方式,尽量减小了端部摩擦效应的影响,同时整个加载系统动态控制,频率高,输入信号多样,可完成多种特殊试验;(5)特殊设计了一种多功能加卸载压头,可完成真三轴应力条件下的水力压裂试验;(6)试验系统可在2个方向分别提供6 000 k N,1个方向提供4 000k N的载荷,同时通过伺服增压系统,最大可提供60 MPa的流体压力。利用一系列测试方法和试验对该系统的准确性和可靠性进行验证,结果表明试验系统准确可靠。该试验系统的研制为研究真三轴流固耦合条件下煤岩的力学特性与流体渗流规律提供新手段,可推进二氧化碳地质储存、油气高效开采和深部岩土工程等问题的深入研究。
[Abstract]:In order to simulate the three direction unequal principal stress state of underground coal and rock mass more realistically, and to reveal the mechanical characteristics of coal and rock and the seepage law of fluid in it under the condition of true triaxial fluid-solid coupling, A multifunctional true triaxial fluid-solid coupling test system is developed. The system consists of frame, true triaxial pressure chamber, loading system, internal sealing seepage system, control and data measurement, acquisition system and acoustic emission monitoring system. The advanced nature and innovation of the system are as follows: (1) it can realize the study of mechanical characteristics of coal and rock and fluid seepage law under the condition of multiple complex stress paths, biaxial and true triaxial stress; (2) in order to realize multiaxial linkage, the center point of the specimen can be kept unchanged. Three new loading and unloading control methods (tracking force Trace-F, tracking displacement Trace-D, tracking displacement correction Trace-Df); (3) are designed for internal seal seepage system combined with servo pressurization system. The control and monitoring of gas-liquid free seepage under true triaxial stress are realized for the first time. (4) the test system adopts a two-direction rigid flexible or rigid loading mode, which minimizes the effect of the end friction effect and the dynamic control of the whole loading system. The frequency is high, the input signal is various, and many special tests can be completed. (5) A multi-function loading and unloading pressure head is specially designed. The hydraulic fracturing test under true triaxial stress condition can be completed. (6) the test system can provide 6 000 KN load in two directions and 4 000 KN load in one direction. At the same time, the maximum fluid pressure of 60 MPa can be provided by the servo pressurization system. The accuracy and reliability of the system are verified by a series of test methods and tests. The results show that the test system is accurate and reliable. The development of the test system provides a new means for studying the mechanical characteristics and fluid seepage law of coal and rock under the condition of true triaxial fluid-solid coupling, and can promote the further research on the geological storage of carbon dioxide, the efficient exploitation of oil and gas, and the deep geotechnical engineering.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学资源及环境科学学院;重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室;
【基金】：国家重点基础研究发展计划(973)项目(2011CB201203) 国家自然科学基金资助项目(51434003,51374256)~~
【分类号】：TU45

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