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针对围岩抗力系数在隧道开挖引起围岩变形应用中的不足,借鉴抗力系数的概念提出了评价围岩承载能力的自承载系数,给出了其物理意义,并以等值地应力作用下深埋圆形隧道为例进行了围岩自承载系数计算式推导与参数影响特性分析。研究结果表明:围岩自承载系数是多种因素共同作用下的综合评价指标,支护力、材料模型、中间主应力、围岩峰后粘聚力、剪胀特性和塑性区弹性模量均对其有显著影响;自承载系数曲线被临界支护力分成弹性和塑性两段,采用理想弹-塑性模型或不考虑剪胀特性均会高估围岩的自承载能力,应充分考虑中间主应力效应并设法提高围岩峰后粘聚力和塑性区弹性模量。
In view of the shortcomings of the surrounding rock resistance coefficient in the application of surrounding rock deformation caused by tunnel excavation, the self-bearing coefficient to evaluate the bearing capacity of surrounding rock is put forward by reference to the concept of resistance coefficient. The physical meaning is given, and under equivalent stress Taking the deep circular tunnel as an example, the calculation formula derivation of the self-bearing coefficient of surrounding rock and the analysis of the parameter influencing characteristics are carried out. The results show that the self-bearing coefficient of surrounding rock is a comprehensive evaluation index under the combined action of many factors. The support force, material model, intermediate principal stress, post-peak cohesion, dilatancy characteristics and elastic modulus of plastic zone Which has a significant impact on it. The curve of self-bearing coefficient is divided into elastic and plastic by the critical supporting force. If the ideal elastic-plastic model or the dilatancy is not considered, the self-bearing capacity of the surrounding rock will be overestimated. Stress effect and try to improve the surrounding rock peak cohesion and plastic zone elastic modulus.