岩石力学与工程学报
巖石力學與工程學報
암석역학여공정학보
CHINESE JOURNAL OF ROCK MECHANICS AND ENGINEERING
2015年
z1期
3037-3044
,共8页
岩石力学%双重孔隙介质%黏聚力%内摩擦角%弹塑性%有限元分析
巖石力學%雙重孔隙介質%黏聚力%內摩抆角%彈塑性%有限元分析
암석역학%쌍중공극개질%점취력%내마찰각%탄소성%유한원분석
rock mechanics%dual porosity medium%cohesion%internal friction angle%elasto-plasticity%FEM analysis
考虑裂隙的连通率、间距、孔隙基质和裂隙材料在表征单元(REV)中的体积分数，认为双重孔隙介质的黏聚力cN及内摩擦角?N是随方向变化的，从而进一步完善相应的确定方法，并证明所建立的cN ，?N计算式是合理的。在独自开发的二维弹塑性有限元程序中引入求得的cN ，?N ，针对一个断面为矩形的地下洞室，拟定岩体中裂隙的连通率及间距不同的2种情况，进行数值模拟，考察围岩中的变形、应力和塑性区的分布与变化。所得结果显示：随着岩体裂隙连通率的增加，岩体的破碎程度变严重，黏聚力和内摩擦角下降，围岩中位移增大，主应力等值线发生明显变化，塑性区加速扩展，并且位移、应力和塑性区的分布由对称变为不对称，围岩的各向异性表现越发显著；而随着裂隙间距的变大，围岩的动态与裂隙连通率增加时正好相反。
攷慮裂隙的連通率、間距、孔隙基質和裂隙材料在錶徵單元(REV)中的體積分數，認為雙重孔隙介質的黏聚力cN及內摩抆角?N是隨方嚮變化的，從而進一步完善相應的確定方法，併證明所建立的cN ，?N計算式是閤理的。在獨自開髮的二維彈塑性有限元程序中引入求得的cN ，?N ，針對一箇斷麵為矩形的地下洞室，擬定巖體中裂隙的連通率及間距不同的2種情況，進行數值模擬，攷察圍巖中的變形、應力和塑性區的分佈與變化。所得結果顯示：隨著巖體裂隙連通率的增加，巖體的破碎程度變嚴重，黏聚力和內摩抆角下降，圍巖中位移增大，主應力等值線髮生明顯變化，塑性區加速擴展，併且位移、應力和塑性區的分佈由對稱變為不對稱，圍巖的各嚮異性錶現越髮顯著；而隨著裂隙間距的變大，圍巖的動態與裂隙連通率增加時正好相反。
고필렬극적련통솔、간거、공극기질화렬극재료재표정단원(REV)중적체적분수，인위쌍중공극개질적점취력cN급내마찰각?N시수방향변화적，종이진일보완선상응적학정방법，병증명소건립적cN ，?N계산식시합리적。재독자개발적이유탄소성유한원정서중인입구득적cN ，?N ，침대일개단면위구형적지하동실，의정암체중렬극적련통솔급간거불동적2충정황，진행수치모의，고찰위암중적변형、응력화소성구적분포여변화。소득결과현시：수착암체렬극련통솔적증가，암체적파쇄정도변엄중，점취력화내마찰각하강，위암중위이증대，주응력등치선발생명현변화，소성구가속확전，병차위이、응력화소성구적분포유대칭변위불대칭，위암적각향이성표현월발현저；이수착렬극간거적변대，위암적동태여렬극련통솔증가시정호상반。
Considering the connectivity rate and spacing of fractures,volume fractions of pore matrix and fracture material in a representative element volume,a method of determining the cohesioncN and internal friction angle N? which vary with direction in a dual porosity medium was suggested,and the equations established for calculating the values ofcN andN? were proved to be reasonable. Introducing the method solvingcN and N? values into the elasto-plastic finite element method(FEM) code,the computations were carried out for a rectangular underground cave for two cases with different connectivity rates and spacing of fractures in a rock mass,and the stresses,displacements and plastic zones in the surrounding rock mass were analyzed and compared with each other. The results show:with the increase of fracture connectivity rate,the cohesion and internal friction angle of the rock mass decrease,the displacements in surrounding rock mass grow,the principal stress contours change obviously,the plastic zones accelerate development,and the distributions of displacements,stresses and plastic zones change from symmetric ones to asymmetric ones,as well as the anisotropy of surrounding rock mass displays more significantly;but with the increase of fracture spacing,the dynamic state of surrounding is just the reverse of what in the case of increasing fracture connectivity rate.
