软弱破碎围岩变形特性

DEFORMATION CHARACTERISTICS OF FRACTURED WEAK ROCKS

本文在连续十余年原位监测试验资料的基础上,描述了全断面开挖的软弱围岩变形u—t全过程曲线;阐明了不同变形阶段的变形速率、变形量以及这些变形的时空效应;探讨了岩体工程地质特性、埋深、洞径、开挖方式和支护及时性等主要因素对围岩变形特性的影响;并针对具体工程提出了围岩稳定性状态划分及其判别标准、失稳险情预报原则、变形控制标准与初期支护抗力的确定原则、后期支护最佳施作时期的选择以及合理开挖方式。

In this paper a u-t curve for the whole process of deformation of the fractured weak rocks during all-section excavating is described from the data of in-situ successive monitoring and measurement for more than ten years, the deformation rate, amount and their effects in time and space are suggested, and the effects of main factors, such as the engineering geological properties, burial depth, opening diameters, excavation modes and in-time supporting, on the deformation characteristics of rocks are discussed. Then the criteria for division and discrimination of stability behaviors of rocks, principles for prediction of instability risk, critera for controlling deformation, principles for determining early support resistance and for selecting optimum period of late supporting, and rational excavation mode are proposed for specific engineering project.