Study On The Microscopic Numerical Calculation Of The Relationship Between Structure Normal Load And Water Pressure In Deep Saturated Pore Rock

With the increase of burial depth,the stress environment in rock mass becomes more complex.In order to explore the mechanism of normal external water load of deep underground structure,numerical simulation method was adopted to study the variation law of normal external load of underground structure under pore water pressure.Firstly,the relationship between pore water pressure and normal load of underground structure under elastic rock condition is studied.The saturated pore rock microelement and underground structure model are established,and the pore pressure-structural normal stress relationship is considered under two conditions of different pore continuity and closure.The influence law of pore water pressure on the equivalent Poisson's ratio and equivalent elastic modulus of saturated pore rock is found,and the influence law of Poisson's ratio,vertical stress,porosity,structural stiffness,matrix yield strength,matrix tangent modulus and other factors on the normal load-pore water pressure relationship of structure is obtained.The results show that the increase of pore pressure leads to the increase of equivalent elastic modulus and Poisson's ratio of rock,which leads to the increase of structural normal stress.There is a linear relationship between pore pressure and structural normal load,and the increment of structural normal load caused by unit increase of pore pressure is equal.When the pores in rock are completely closed and disconnected,the equivalent elastic modulus of rock mass is not affected by pore water pressure and vertical total stress.Secondly,the relationship between pore water pressure and normal load of underground structure under elastoplastic rock condition is studied.The applicability of the effective stress formula in saturated pore rock mass and the accuracy of the stress balance formula in the calculation of micro-element section load of rock are verified.The significance of the influence of each factor on the relationship between unit pore water pressure increment and structural normal stress change is obtained,and the accuracy of the correction results of structural normal hydraulic load by different correction factors is verified.The results show that the slope of the structural normal stress-pore pressure relation curve is approximately equal for elastic and elastoplastic rock.The effective stress formula and definition are not applicable to saturated pore rock,but the stress balance theory is accurate to describe the stress of rock cross-section.When the hydraulic load correction factor?=1 is considered,the calculation results are too conservative and the structure stability is high but the economy is poor.When the correction factor?=n,the calculated results are too radical and the structure safety is poor.The correction factor value should be between n and 1.In the pore connected rock,the modified results using?=1-C_S/C and?=1-(1-n)Cs/C can conform to the rule of structural normal stress variation under unit pore water pressure increment.Therefore,they are suggested to be used as a reference theory in underground structure design.In this thesis,there are 59 figures,30 tables and 84 references.