基于摩尔库伦准则的岩石地基极限承载力研究

Study on the Ultimate Bearing Capacity of Rock Foundation based on Mohr-Columb Criterion

由于没有考虑围压,现行规范利用单轴抗压强度确定的岩石地基承载力通常是偏低的。现场岩基载荷试验是目前确定岩石地基极限承载力的可靠方法,但在勘察阶段地基尚未开挖形成,直接进行载荷试验难以实现。岩石三轴压缩试验与岩石地基的实际受力状态相似,利用岩石三轴压缩试验成果,岩石地基的极限承载力是可以确定的。依据莫尔库伦强度准则和广义胡克理论确定岩石地基破坏的临界围压,由此推导出岩石地基极限承载力的理论公式,该公式是岩石地基极限承载力计算的新方法,其物理意义明确,可直接利用室内试验成果进行地基极限承载计算,方便实用,具有一定的工程意义。

Without considering confining pressure, the bearing capacity of rock foundation is usually undervalued in current standards in which the bearing capacity is determined by uniaxial compressive strength. The ultimate bearing capacity of rock foundation is usually determined by loading test,but rock foundation has not been formed during geotechnical investigation stage,therefore loading test is difficult to achieve. The stress condition of triaxial-compressive test is similar to rock foundation condition. For this reason,the ultimate bearing capacity can be determined by triaxial compression test. Based on Mohr-Coulumb strength criterion and Hooke theory,the critical confining pressure when rock foundation broken is determined,and the ultimate bearing capacity theoretical formula of rock foundation was eventually established. As a new calculating method,this formula can be solved directly through laboratory data,which has significant physical and practical meanings.