论文部分内容阅读
为了研究采空区影响下地表建(构)筑物的变形与破坏,必须首先全面认识建(构)筑物地基土的结构力学特性。基于综合结构势理论,利用TSW-40型土壤真三轴仪,以南票矿区松散层土体为研究对象,开展一系列不同围压、含水率和中主应力比条件下的真三轴试验,揭示了真三维应力状态下松散层土体应力比结构性参数的变化规律,建立了结构性参数数学模型。研究结果表明:原状土的q-ε_s曲线呈现出应变软化型、理想弹塑性型和应变硬化型3种典型的状态。重塑土和饱和土q-ε_s曲线一般均表现为应变硬化型。应力比结构性参数m_η随剪应变、含水率、固结围压和中主应力比的增加而降低;剪切作用初始阶段,m_η下降较快,当ε_s达到5%左右后,m_η逐渐趋于平稳,至ε_s=15%时,m_η趋近于1;结构性参数数学模型结果表明,固结围压对m_η影响最大,含水率次之,中主应力比对m_η影响最小。利用所建立的数学模型预测不同试验条件下松散层土体结构性参数变化规律,模型验证结果与试验结果吻合,证明了模型的有效性,可以作为进一步研究的理论基础。
In order to study the deformation and destruction of the surface structures under the influence of the goaf, we must first fully understand the structural mechanics characteristics of the foundation soil of the building structures. Based on the theory of synthetic structure potential, a series of true triaxial tests under different confining pressures, water cut rates and intermediate principal stress ratios were carried out by using TSW-40 soil true triaxial apparatus and the loose soil in Nantou Mining Area. , Reveals the variation law of stress ratio of structural parameters of loose soil in true three-dimensional stress state, and establishes the mathematical model of structural parameters. The results show that the q-ε_s curve of undisturbed soil shows three typical states of strain softening, ideal elastoplasticity and strain hardening. Remodeling soil and saturated soil q-ε_s curve are generally manifested as strain hardening type. M_η decreased with the increase of shear strain, water cut-off, consolidation confining pressure and middle principal stress ratio. In the initial stage of shearing, m_η decreased rapidly. When ε_s reached about 5%, m_η gradually tended to When ε_s = 15%, m_η approaches 1; the structural parameter mathematical model shows that the consolidation confining pressure has the strongest influence on m_η, the second is the water content, and the middle main stress has the least effect on m_η. Using the established mathematical model to predict the variation of structural parameters of loose soil under different test conditions, the model verification results are in good agreement with the experimental results, which proves the validity of the model and can be used as theoretical basis for further study.