基于统一强度理论朗肯土压力的计算研究

 采用双剪统一强度理论主应力型表达式和平面应变假设，首先将挡土墙土压力问题视为平面应变问题，通过广义虎克定律确定出中主应力 ，并根据朗肯土压力分析原理确定出另外一个主应力，最后结合双剪统一强度理论主应力型表达式分别推导朗肯主动土压力和被动土压力的计算公式。该公式除了引入考虑中主应力影响的系数b，还通过广义虎克定律把材料的泊松比 引入朗肯土压力计算公式中。经典的朗肯土压力计算公式仅为该统一解的特例。该统一解可以灵活地运用于各种不同特性填土材料的土压力计算。最后通过一算例讨论不同权系数b对计算结果的影响。分析表明：采用经典的朗肯被动土压力理论所得到的结果是偏小的，而采用经典的朗肯主动土压力理论所得到的结果是具有一定的安全储备；双剪统一强度理可以更好地发挥材料的强度潜力，可取得一定的经济效益。

CALCULATION STUDY OF RANKINE EARTH PRESSURE BASED ON UNIFIED STRENGTH THEORY

The issue of wall earth pressure will be regarded as problem of plane strain，so intermediate principal stress is calculated by generalized Hook¢s law in plane strain assumption. The principal stress in accordance with the principle of Rankine earth pressure is determined. On this basis，the formula of Rankine earth pressure is derived when the expression of principal stress in double-shear unified strength theory is used. The weighted coefficient b considering effects of intermediate principal stress and the Poisson's ratio is introduced to the formula. The solution based on classical Rankine active earth pressure theory is a special case of the unified solution. The unified solution can be flexibly used to calculate earth pressure of various filled materials. Finally，an example is given to show the impact of their results in different weighted coefficients b. The analytical shows that the result of classical Rankine passive earth pressure theory is smaller，so it often causes the potential danger. However，the result of classical Rankine active earth pressure theory is larger and has enough safety storage. The potential strength of filling materials is sufficiently developed under the guidance of the double-shear unified strength theory，so some economic benefits can be obtained.