软化Drucker-Prager材料强度参数的测定方法  

A METHOD FOR MEASURING STRENGTH PARAMETERS OF SOFTENING DRUCKER-PRAGER MATERIAL

作　　者：姚再兴[1,2] 

机构地区：[1]煤炭科学研究总院矿山安全技术研究分院,北京100013 [2]北京大学工学院,北京100080

出　　处：《岩石力学与工程学报》2014年第6期1187-1193,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：煤炭科学研究总院科技发展基金资助项目(2011CX04)

摘　　要：通过回顾Drucker-Prager材料强度参数随内变量变化时应该满足的本构关系,给出在常规三轴试验机工况下的简化表达。选择轴向塑性压应变作为内变量,得到内变量增量与应变增量和应力增量之间的关系,从而得出各试验记录点对应的内变量。为通过多次试验确定对应同一内变量的2个强度参数,把各次试验的应力在均匀离散的内变量点上进行插值,使各次试验对同一内变量按屈服面方程求解强度参数的方程成为可能。得到一种不预设强度参数变化模式也可确定强度参数变化规律的方法。实例分析结果显示试验材料的2个强度参数变化趋势并不一致,不同围压下轴向应力达到峰值对应的内变量也不同,这与围压可提高强度极限并推迟强度极限到来的观点是一致的。A simplified expression under conventional three axis test conditions is presented after reviewing the constitutive relation of Drucker-Prager material with the parameters changing with internal variables. The axial plastic strains were selected as the internal variables and the relations between the increments of internal variables and the ones of external variables of strains and stresses were obtained. The values of internal variables at each point of recording in testing were thus obtained. In order to determine the values of two strength parameters corresponding to the same internal variable through a number of tests, the stresses of each test were interpolated among uniformly distributed values of internal variables; so that the strength parameters for a given internal variable can be derived from the yield surface equation. As such the variations of the strength parameters with the internal variables were obtained without the need of assuming one beforehand. Results of tests show that the variations of two strength parameters are not the same and the values of internal variables at peak stresses are different under different confining pressures, which agrees with the viewpoint of others that confining pressure can improve the ultimate strength and delay its coming.

关 键 词：岩土力学 Drucker-Prager材料 屈服面 强度参数 塑性软化 

分 类 号：TU41[建筑科学—岩土工程]