非线性弹性模量对波速影响的实验研究

Experimental Research on the Effect of Nonlinear Modulus on Velocity

在循环应力作用下 ,对砂岩和石英砂两种结构较松散的样品进行了实验研究。对非线性模量与应变的关系作了非线性拟合 ,用非线性模量来代替弹性模量 ,对弹性介质中的波速公式作了修正。将波速与应力的多值函数关系转化成波速作为应变 (或密度 )的单值函数。同时考虑了水饱和对非线性模量和波速的影响 ,得出了速度与应变的拟合关系曲线。实验数据和理论曲线有较好的一致性。

Experiments are made on sandstone and quartz powder,whose structures are incompact under the function of cyclic stresses.The nonlinear fitting is made on the relations between the nonlinear modulus and strain.The velocity formula in the elastic medium is corrected by using nonlinear modulus instead of elastic modulus.The multi-value function for velocity to stress is transformed into a single value function for velocity to strain(density).Meanwhile,considering the effect of water saturation on the nonlinear modulus and velocity,the fitted relation curves between the velocity and the strain are obtained.The theory curves have good coherence to experimental data.