基于P-R相关性研究的岩石地基承载力优化取值  

Optimization of bearing capacity of rock foundation based on study of relativity of P-R

作　　者：李维树[1,2] 黄志鹏[1,2] 周火明[1] 景锋[1] 

机构地区：[1]长江科学院水利部岩土力学与工程重点实验室,武汉430010 [2]长江科学院重庆岩基研究中心,重庆400014

出　　处：《岩土力学》2009年第12期3700-3704,3714,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.50639090);水利部岩土力学与工程重点实验室开发基金资助项目(No.G07-16)

摘　　要：岩石地基承载力是建筑工程中一个重要的力学指标,大多数建筑工程主要依据岩石饱和单轴抗压强度的标准值R确定,重要建筑工程还需要通过岩体载荷试验的承载力特征值P确定,那么两种方法必然存在一定的相关性。实践经验表明,用R确定承载力的方法简单易行,但R代表的是岩石材料的特性,与工程岩体的情况有显然的不同,而原位载荷试验是在半无限条件下进行的,与工程实际条件更为接近,因此,用P确定地基承载力比用R要合理。在总结多达43点的岩体载荷试验及对应部位至少3组的单轴抗压强度对比试验成果与收集248组重庆地区岩石的三轴强度试验成果的基础上,建立了P-R相关关系及围压条件下的强度特征。通过揭示它们之间的相关性,提出采用岩石饱和单轴抗压强度标准值的1.5倍作为地基承载力特征值的重要结论,为岩石地基承载力优化取值提供了重要依据。Bearing capacity of rock foundation is an important index in civil engineering. It is based on the uniaxial compression strength R of saturated rock for most civil engineering, and also based on the eigenvalue P of plate loading test for important engineering. Thus, the two methods must have some relativity. It is indicated in the practices that the R method is simple and easy for handling; but R represents characteristics of rock materials which is quite different from the condition of the engineering rock mass. Plate loading test is carried out under the semi-infinite condition; it is more close to the engineering practice. Therefore, the P method is more reasonable than the R method. This article establishes the relativity of P-R as well as the strength characteristics under surround compression on the basis of summarizing 43 plate loading tests results and three groups of uniaxial compression strength tests results on the same position, and collecting 248 groups of triaxial compression test results in Chongqing area. By demonstrating the relativity of P-R, the article brings forward an important conclusion of taking rock saturated uniaxial compressive strength of the standard value of 1.5 times the characteristic values as a foundation bearing capacity of the important conclusions, so as to provide an important reference for optimization of bearing capacity of rock foundation.

关 键 词：岩石地基承载力 P-R相关性 载荷试验 饱和单轴抗压强度 优化取值 

分 类 号：TB125[理学—工程力学]