川中红层岩体结构裂隙发育特征及多尺度分析

四川盆地红层岩体宏细观裂隙发育,是影响其卸荷变形、吸水风化膨胀和工程特性的控制因素,近年来出现的多起高速铁路深挖红层路堑型路基持续超限上拱变形病害与此有关.为了解红层软岩裂隙发育特征,在原位岩体所有节理裂隙进行现场调查和测量统计基础上,采用统计岩体力学的方法,从不同尺度对岩体结构裂隙进行了深入系统的分析.结果表明,大尺...

Fracture development characteristics and multi-scale analysis of red bed rock mass in central Sichuan

The development of macro and micro fracture in red bed rock mass in Sichuan Basin is the controlling factor that affects its unloading deformation, water absorption, weathering and expansion and engineering characteristics. In recent years, a number of continuous over-limit upper arch deformation diseases of deep red bed cut roadbed for high-speed railway appeared, which is related to this.In order to understand the characteristics of fracture development in red-bed soft rock, based on the field investigation and measurement statistics of all joints and fractures in in-situ rock mass, the method of statistical rock mechanics was adopted to conduct in-depth and systematic analysis of structural fractures in rock mass from different scales.The results show that the large scale fractures are mainly in the primary sedimentary layer, which shows the obvious phase transition.Mesoscale and small scale fracture of structural and denudation unloading unharmony deformation cause local complex stress field caused by combined action, deep cut excavation unloading exacerbated the extensional fractures development, mainly meso-scale crack, crack length distribution are two scales accords with negative exponential model, the development advantage direction perpendicular to the plane, and based on the macro rock mass structural plane characteristics analysis of the results;This model can be applied to engineering practice. Through the analysis of the development characteristics of mesoscale fractures, which is easy to map and statistics, the geological environment model and fracture structure framework of the whole formation of red-bed rock mass can be established, and then the mechanical properties of red-bed rock mass and the deformation and stability of red-bed engineering rock mass can be more objectively evaluated.