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将断裂力学引入裂隙岩体流固耦合分析,建立裂隙岩体渗流-断裂耦合机制,在FLAC3D现有计算模块的基础上,通过FISH研制了裂隙岩体渗流-断裂耦合分析程序。该模型的耦合机制体现在:渗透水力梯度作为渗透体积力作用于应力计算单元,裂隙渗透压作为面力作用于裂纹张开部分引起断续岩体裂纹的劈裂扩展;岩体裂纹的扩展引起岩体渗透系数的增加导致渗流场的改变。将渗流-断裂耦合理论应用于高水头不衬砌压力隧洞工程中,系统地研究高水头不衬砌压力隧洞在运行期间的水力劈裂、渗流场和内水外渗渗漏情况,得到:①处于水力劈裂的高水头压力隧洞周边向外延伸依次为拉剪劈裂区、压剪劈裂区、未劈裂区;②由于渗流体积力作用,高水头压力隧洞内水外渗过程中洞周产生径向向外变形;③高水头压力隧洞内水外渗过程中渗漏率先增加后平稳减少最终稳定。首次提出陡倾地表下不衬砌压力隧洞与裂纹几何特性、力学特性和岩石断裂韧度高度相关的水力劈裂系数的概念。建议在水工隧洞设计规范中建立与水力劈裂系数相匹配的安全控制标准,可为我国不衬砌压力隧洞工程的设计提供理论基础。
The fracture mechanics is introduced into the fluid-structure coupling analysis of fractured rock mass, and the seepage-fracture coupling mechanism of fractured rock mass is established. Based on FLAC3D existing computational module, a coupled flow-fracture coupling analysis program of fractured rock mass is developed by FISH. The coupled mechanism of the model is as follows: the hydraulic gradient of infiltration acts as the volume of permeation force on the stress calculation unit, and the osmotic pressure of fractures acts as the surface force on the open part of the crack to cause the splitting and propagation of cracks in the discontinuous rock mass; The increase of permeability coefficient of rock mass leads to the change of seepage field. The theory of seepage-fracture coupling is applied to the high-head and linerless pressure tunnel project. The hydraulic fracturing, seepage field and leakage of internal water seepage during the operation of the high-head and linerless pressure tunnel are studied systematically: (1) The periphery of the high-head hydraulic fracturing tunnel extends outwards in the order of tension-shear splitting zone, pressure-shear splitting zone and un-splitting zone. ② Due to the effect of seepage volume force, Radial outward deformation; ③ high head pressure tunnel infiltration process within the water leakage increased first and then steadily reduce the final stability. For the first time, the concept of hydraulic fracturing coefficient which is highly correlated with crack geometry, mechanical properties and fracture toughness of rock under non-lining pressure tunnel under steep subsidence is first proposed. It is suggested to establish a safety control standard that matches with the hydraulic split coefficient in the design specification of hydraulic tunnel, which can provide the theoretical basis for the design of non-lining pressure tunnel in our country.