土石料湿化变形计算方法探讨

Calculation method of wet deformation of earth-rock materials

土石料的湿化是一种普遍现象,虽然可以利用非饱和理论计算湿化变形,但人们更愿意采用常规的初应变法进行计算,湿化试验则常用单线法或双线法进行。对湿化试验和相关计算方法进行分析,提出考虑湿化变形及其影响的新思路,(1)在某一应力状态下的湿化变形是由两部分组成的,一部分是由于材料本身刚度变'软'引起的湿化变形,另一部分变形是湿化引起的附加变形;(2)在双线法试验中直接将相同应力状态下对应干土和湿土的应变相减计算是不合适的,应当采用相同应力状态下各自的切线模量计算;(3)基于广义位势理论,根据应力和应变的对偶特性,可以把湿化附加变形变换为一种湿化等效应力,虽然其是一种近似处理方法,但它比较简单,容易直观地量化湿化的作用。文中思路对于颗粒破碎、干湿循环引起的变形、流变变形等也具有借鉴意义。

It is quite common that deformation occurs when earth and rock materials are wet.Generally,initial strain method is more popular than the theory of unsaturated soil in calculating the wetting deformation.The wetting tests are usually carried out by single line method or double line method.In this paper,the wetting tests and relevant calculation methods are used to calculate the wetting deformation and related influence parameters,and a new approach in calculating wetting deformation and its influence is put forward,which mainly involves:(1)under a certain stress state,wetting deformation actually includes two components,one is induced by the‘soft’effect of the soil’s stiffness,the other is the‘real’additional deformation induced by wetting.(2)It is unsuitable to directly subtract the deformation of‘dry soil’from that of the‘wet soil’at the same stress state in the double line test.The subtraction should be calculated by using the tangent modulus under the same stress state.(3)Based on the generalized potential theory and the dual properties of stress and strain,one can transform the effect of the wetting deformation into an equivalent stress.Although this is an approximate method,it is simple and easy to quantify the wetting effect.This idea can also be used to investigate the effect of rheological deformation and the deformation caused by particle breakage and drying-wetting cycles.