Study on Water-rock Interaction Effect Test and Tunnel Seepage Intelligent Back Analysis
|School||Dalian Maritime University|
|Course||Traffic and Transportation Engineering|
|Keywords||Water-rock interaction Acoustic emission test Seeping under HighConfining Pressure Differential evolution Seepage back analysis|
Water rock interaction is the unavoidable problem of underground works. With the development and needs of underground works,people from all walks of life are increasingly concerned about it. Water rock interaction can be divided into two branches. One is about water chemistry, to explore the origin of water in the earth, the spatial and temporal distribution of water quality law,the various factors of its impact and the chemical evolution of water. The other is about the dynamics of the water, that water-rock coupling, the hydrodynamic field in the geological environment and the spatial and temporal distribution which is caused by the interaction between the crustal stress field. These two branches can be summarized as the study of the chemical reaction of water and the role of fracture seepage.This paper is based on experiments, the combination of theory and research of various disciplines.Simulated with the numerical simulation softwares. Analyze and explore the impact of water-rock interaction on rock strength, structure and permeability.The main conclusions can be drawn as follows:l.The split tests with different external environment and standing time show that the aging recovery of the Kaiser effect is influed by the liquid immersion.Use RFPA2D to simulate the specimens witn different homogeneities and compared the smulation results and the experimental results.The homogeneities of the specimens which are soaked in fresh water are lager than dry standing. The homogeneities of the specimens which are soaked in fresh water are smaller than dry standing.The homogeneity of the rock is influed by the external environment.2.Combine the high hydraulic fracture seepage test results with FLAC3D simulation to prove that:when the permeability coefficient is changed because of a change in the gap width with the high osmotic pressure, Darcy’s law is still applicable.Propose the ideas of the fissures intrinsic opening and the intrinsic permeability coefficient caused by intrinsic opening.When the fracture aperture is small, the intrinsic permeability coefficient must be considered. Prove that the flow velocity not only depends on the osmotic pressure difference,it also depends on the confining pressure and the hydraulic pressure of the specimen. The fundamental reason is the confining pressure and the hydraulic pressure change the fissures opening. 3.In the example of Malan River underground tunnel of Dalian subway208tenders,use the differential evolution seepage inverse analysis method to inverse the permeability coefficient of the surface gravel layer and the underlying weathered rock.And also consider the anisotropy of the permeability of the soil. The monitoring level information from the permeability coefficient of the back analysis meet the engineering requirements, this demonstrates that the algorithm is applicable to complex terrain.