三向高应力状态下深埋大理岩变形特性试验研究

为获得深部岩体的变形模量，在真三轴试验机上，对中等尺寸大理岩试样进行不同侧压下的变形试验，重点对同一试样进行多个等侧压和不等侧压的对比试验。试验表明：(1) 大理岩的变形模量与侧压之间具有显著的非线性关系，且当侧压增大至30 MPa后，变形模量不再随着侧压的增大而显著增大，该侧压值反映了大理岩脱离母岩后的弱化程度；(2) 建立大理岩的变形模量与三向应力之间的关系，用试样所对应部位地应力值计算出深埋大理岩的变形模量为66.7～68.2 GPa；(3) 变形模量计算值与采用其他间接方法获得的变形模量相当，并显著高于常规室内和现场变形试验值。由此说明，深部岩体在释放应力后容易使其力学性质弱化，弱化程度与所处的地应力大小有关。该方法对研究极高～高地应力环境下深部岩体及偏应力较大的边坡的变形特征具有重大意义。

EXPERIMENTAL STUDY OF DEFORMATION CHARACTERISTICS OF DEEP MARBLE UNDER THREE-DIMENSIONAL HIGH STRESS

To obtain the deformation modulus of deep rockmass，deformation tests under different lateral pressures are carried out for medium size marble samples using the true triaxial test machine. The comparison tests for the same sample under the same lateral pressure and different lateral pressures are conducted emphatically. The tests indicate that：(1) There is significant nonlinear relationship between deformation modulus and lateral pressure of the marble. The deformation modulus of marble no longer increases with the increase of the lateral pressure after the lateral pressure reaches 30 MPa；and the lateral pressure reflects the weakening degree of marble when the marble breaks away from parent rock. (2) Then，the relationship between deformation modulus and three-dimensional stresses of marble is obtained. Based on the value of in-situ stress at the site of the sample，the deep marble deformation modulus of 66.7–68.2 GPa is calculated. (3) The calculated value of deformation modulus coincides well with the value obtained by other indirect methods；and it is significantly higher than values of conventional indoor and field tests. The above results indicate that the mechanical properties of deep rock mass will be weakened after stress relief；and the weakening degree is related to the in-situ stress. This method is of great importance for researching deformation characteristics of rock mass under high in-situ and extremely high stress and slopes with larger deviatoric stress.