浅表风化混杂土石体特定比对物的力学特性试验研究

在土石混合体力学特性研究中,试验样本通常取自实际工程,所含物质成分复杂多样,使得试验结果离散程度较高、可验证性较差,所得结论尤其是其结构性与宏观力学行为间的关联对工程实际的指导意义体现不足。为此,从物质组成的角度设计一种特定土石混合体材料:块石均为未风化的同种岩石,基质土为矿物组成相同的同种土。该材料物质成分均一、稳定,具有可验证性。本文以此为比对物试样,基于室内大型三轴试验,在验证试验结果可重现性的基础上,重点分析块石级配、制样干密度、块石分布三种宏观尺度结构性指标对特定土石混合体应力一应变特性、强度特征参数、初始弹性模量的影响规律;将试验结论与已有研究成果进行了比对;对昭山残坡积堆积体力学特性进行了推定与验证。结果表明:特定土石混合体在同一工况下的试验具有较好的可重现性;粗粒含量较高时,应力一应变曲线存在锯齿状波动,并呈现“台阶状”走势;试验得出两类典型应力一应变曲线;不同块石空间分布下试样出现不同的变形破坏特征;细粒含量与10~40mm粗粒粒组含量对强度指标影响较大;试验得出已有研究共性成果之外的结论,有利于区分试验结果中的现象与规律,能够为类似工程实践提供更可靠的理论指导。

Experimental study of mechanical properties of specific comparison object for shallow weathered mixed soil and rock

In the study of mechanical properties of soil-rock mixture, the samples are usually taken from practical engineering, and the material composition is complex and diverse, which makes the experimental results more discrete and less verifiable. The obtained conclusions, especially the relationship between its structure and macroscopic mechanical behavior, are insufficient in guiding engineering practice. Therefore, from the point of view of material composition, a special mixture of soil and rock is designed. Its rock block is the same rock with unweathered rock, and the matrix soil is the same soil with the same mineral composition. The material is homogeneous, stable and verifiable. In this paper, taking this specific comparison object as samples, based on lab large-scale triaxial tests and verification of reproducibility of test results, the influence laws of stone gradation, dry density and stone distribution on the stress-strain behavior, strength characteristic parameter and initial elastic modulus were explored. The test conclusions were compared with the existing research results. The mechanical properties of the Zhaoshan residual-slope accumulation were estimated and verified. The results showed;The test of the specific soil-rock mixture under the same conditions had good reproducibility. When the coarse grain content was high, the stress-strain curve had a jagged fluctuation and ladder-like trend. Two typical stress-strain curves were obtained. The specimen had different deformation and damage characteristics under different stone distribution. The content of fine particles and the content of 10?40mm coarse grained group had a great influence on the strength index? Conclusions different from common results, were conducive to distinguish between the phenomena and laws in the test results, but also provided more reliable theoretical guidance for similar engineering practice.