论文部分内容阅读
临界状态土力学理论在描述细颗粒土应力变形特性方面较为成功,已经成为建立许多黏土和砂土本构模型的基础。对于堆石料,在应力、密度、级配等因素影响下,其变形特性非常复杂,且高应力条件下颗粒易发生破碎,是否存在“唯一”的临界状态值得探讨。通过对不同级配、不同密度的试样在不同围压条件下的一系列大型三轴剪切试验,研究了堆石料的临界状态及其影响因素。研究发现:不同级配、不同密度、不同初始固结应力条件下,当剪应变较大时试样都趋于临界状态,临界状态的值与初始密度、初始级配、颗粒破碎有关;q–p’平面内,堆石料存在唯一的临界应力比M;在e–(p’/p_a)~ζ平面内,临界状态线基本平行,其截距可以根据初始密度和初始级配直接求得。通过对比分析各试样的临界状态,提出了考虑级配和颗粒破碎影响的堆石料临界状态数学表达式。
The critical mechanics of soil mechanics has been successful in describing the stress-strain behavior of fine grained soils and has become the basis of many constitutive models of clay and sand. For rockfill materials, under the influence of stress, density and grading, the deformation characteristics are very complicated, and the particles are easily broken under high stress conditions. Whether the existence of the “only” critical state is worth discussing. Through a series of large-scale triaxial shearing tests with different graded and densified specimens under different confining pressures, the critical state of rockfill and its influencing factors were studied. The results show that under different grading, different density and different initial consolidation stress, the specimen tends to be critical when the shear strain is large, and the critical value is related to the initial density, initial grading and particle breakage; q- In p ’plane, there is a unique critical stress ratio M; in the e- (p’ / p_a) ~ ζ plane, the critical state lines are basically parallel, and the intercept can be directly calculated from the initial density and the initial grading. By comparing and analyzing the critical state of each sample, the mathematical expression of critical state of rockfill considering gradation and particle breakage is put forward.