论文部分内容阅读
崩积体是一种由土体和块石堆积形成的天然地质体,其内部结构特征在很大程度上控制着崩积体的物理力学特性。通过对崩积体进行现场实地踏勘,收集典型工点的崩积体试样,考虑原样级配,开展了对崩积体重塑样的室内大尺度直剪试验,获得了不同含石量、块石形状、土体性质以及应力状态下崩积体的剪应力-应变曲线与抗剪强度曲线,分析并探讨了其变形与强度特性变化规律及内在机制,首次提出了崩积体抗剪强度随含石量增长模式曲线。研究结果表明:崩积体剪应力-应变曲线较常规的单一介质有显著区别。在低法向应力下,崩积体表现为剪胀,而在高法向应力下,则表现为先剪缩后剪胀。崩积混合体的抗剪强度随含石量的增加经历了缓慢增长-快速增长-缓慢增长的过程,其内摩擦角增量与含石量(含黏性土崩积体为0～80%,含砂土崩积体为40%～80%)近似成线性增长的关系。相同含石量情况下,含不规则形状块石的崩积体内摩擦角显著高于含规则形状块石的混合体。
Collapse is a natural geological body formed by the accumulation of soil and rock mass. Its internal structural features largely control the physical and mechanical properties of the sedimentary body. Through the on-the-spot survey of the deposit, a typical sample of the colluvial body was collected. Considering the grading of the original sample, a large-scale indoor direct shear test was carried out on the gravimetric sample, Stone shape, soil properties and stress-strain state under shear stress-strain curve and shear strength curve, analyzed and discussed the deformation and strength characteristics of the variation and internal mechanism, for the first time put forward the collapse body shear strength with Stone content growth pattern curve. The results show that the shear stress-strain curve of the deposit is significantly different from the conventional single medium. In the low normal stress, the collapse of the body showed dilatancy, while in the high normal stress, the performance of the first shear after dilatation. The shearing strength of the aggregate decreases with the increase of the amount of stone, which shows a slow increase, a rapid increase and a slow increase. The increase of internal friction angle and the amount of stone content (including cohesive soil compaction body is 0 ~ 80% , Sandy loam compacts 40% ~ 80%) approximately linear growth relationship. Under the same condition of stone content, the rubbing angle of the aggregates with irregular shaped rock is significantly higher than that with the regular shaped rock.