岩体初始地应力场分析方法研究

初始地应力场是影响岩土工程稳定性的重要因素之一,如何合理地模拟初始地应力场一直是岩体力学中的重要研究课题。以国内某大型水利水电工程构筑区域实测空间地应力资料为基础,以边界位移为控制对象,采用有限元(无界元)方法对工程区大范围内的岩体初始地应力场进行了分析和研究。尝试在实际边界上满足无穷远处位移为0的模型边界上引入了无界单元,实测点上的应力拟合结果有较明显的改善,这表明所采用的方法是切实可行和有效的。

Study on fitting analysis of initial stress field in rock masses

Initial stress is one of the important factors affecting the stability of geotechnical engineering.How to reasonably simulate the initial stress field is always an urgent problem in rock mass mechanics.Based on the 3-D stress measurements of a certain large-scale hydropower station construction site,the initial stress field of rock masses is analyzed by finite element method,The numerical model is established according to the topographical characters and real geometry of large structures and faults located at the site.The stress field at any point is thought to be composed of gravitational and tectonic stress components,while the gravitational stress component is assumed to be known as the results calculated by finite element method.When fitting the total tectonic stress component at the measurement points,unit normal displacement is applied to the model boundaries and the response is computed at the location of the measurement points in the model.In order to reproduce the measured stress at the measurement point,a linear regression expression is used to calculate the proportions of each unit response tensor.In addition,infinite element is also attempted to be introduced into the model of initial stress field analysis to meet the requirement of zeros displacement values on the boundaries;the preferable results obtained demonstrate that this method is powerful and feasible.