基于地表实测爆破振动的岩体动力学参数快速反演方法

Inversion of dynamic parameters of rock mass based on field blasting vibration

岩体动力学参数的准确、快速获取对水利工程设计、施工及建设起着重要作用。尽管可通过现场原位试验、经验关系法等传统方法对其进行评估,但上述传统方法均存在耗时长、投资大等缺点,且难以准确快速的获取大尺度岩体动力学参数。本文通过分析地表实测爆破振动波形,识别出各测点P、S波初至到时,进一步给出各个测点区间内P、S波的平均传播速度,提出基于地表实测振动的岩石动力学参数预测方法。并以丰宁抽水蓄能电站为例,基于爆破试验实测振动数据反演的岩体动态模量约为北京勘测设计研究院推荐使用的静态模量值的2.2～2.9倍,动泊松比为静泊松比的0.9～0.975倍。提出的基于地表实测振动预测岩体动力学参数的方法为工程尺度下快速获取岩体动力学参数提供了一条新途径。

How to obtain the dynamic parameters of rock mass quickly and precisely is a popular and difficult problem in geotechnical engineering,which plays a very important part in the engineering design or construction.Currently,scholars have developed many methods to obtain these parameters,such as in-situ testing method,empirical formula and so on.However,these methods need large investments and long construction period,etc.,which cannot obtain the dynamic parameters precisely and quickly in the engineering scale.A new method for estimating the rock parameters based on field blasting vibration signals is proposed.By identifying the arrival times of P and S waves,the propagation velocities of P and S waves are calculated,and the parameters can be obtained.By analyzing the field blasting vibration signals in Fengning pumped-storage power station,the results demonstrate that the dynamic elastic modulus of the rocks inversed by the field blasting vibration signals is higher than its static one given by Beijing Engineering Corporation Limited,i.e.the ratio is about 2.2~2.9,and the inversed dynamic Poisson’s ratio is lower than its static one,0.9~0.975 times the static one.Therefore,the proposed method based on field blasting vibration provides a new and effective way for obtaining the dynamic parameters of rock mass.