川中红层岩体结构裂隙发育特征及多尺度分析  

Fracture Development Characteristics and Multi-scale Analysis of Red Bed Rock Mass in Central Sichuan

作　　者：吴沛沛[1] 钟志彬 余雷 王园园[4] 邓荣贵[4] 刘宇罡 WU Pei-pei;ZHONG Zhi-bin;YU Lei;WANG Yuan-yuan;DENG Rong-gui;LIU Yu-gang(China Railway Eryuan Engineering Group Co., Ltd., The Second Civil Engineering Design and Research Institute, Chengdu 610031, China;College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu 610059, China;Design Appraisal Center, China Railway, Beijing 100844, China;School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China)

机构地区：[1]中铁二院工程集团有限责任公司土建二院,成都610031 [2]成都理工大学环境与土木工程学院,成都610059 [3]中国国家铁路集团有限公司设计鉴定中心,北京100844 [4]西南交通大学土木工程学院,成都610031

出　　处：《科学技术与工程》2022年第5期2024-2031,共8页Science Technology and Engineering

基　　金：中国国家铁路集团有限公司重大课题(K2019G045);国家自然科学基金(51808458,41272321)。

摘　　要：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,大尺度裂隙多为原生沉积层面,显示地层相变明显;中尺度和小尺度裂隙多为构造及剥蚀卸荷非协调性变形引起局部复杂应力场共同作用所致,深路堑开挖卸荷加剧了张性裂隙发展,以细观尺度裂隙为主,两种尺度裂隙长度分布均符合负指数模型,发育优势方向多垂直于层面,与基于岩体宏观结构面特征的分析结果吻合;该模型可以应用于工程实际,通过易于测绘统计的中尺度裂隙的发育特征分析,建立红层岩体整体形成的地质环境模型及裂隙结构框架,进而对红层岩体力学特性和红层工程岩体变形及稳定性进行更客观的评价。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,there have been a number of high-speed railway deep excavation red bed cutting subgrade continuous over limit camber deformation diseases 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 fractures are mostly caused by the combined action of local complex stress field caused by non coordinated deformation of structure and denudation unloading.The excavation and unloading of deep cutting intensifies the development of tensile fractures,mainly mesoscale fractures.The length distribution of fractures in both scales conforms to the negative exponential model,and the dominant direction of development is mostly perpendicular to the layer.It is consistent with the analysis results based on the characteristics of rock mass macro structural plane.The model can be applied to engineering practice.Through the analysis of the development characteristics of mesoscale fractures that are easy to map and statistics,the geological environment model and fracture structure framework for the overall formation of red bed rock mass are established,and then the mechanical properties of red bed rock mass and the deformation and stability of red bed engineering rock mass are evaluated more objectively.

关 键 词：红层软岩 多尺度结构裂隙 裂隙网络 岩体结构 

分 类 号：TU45[建筑科学—岩土工程]