麦壳/稻壳加筋黏性土力学性质的试验研究与本构模型

In a variety of reinforcement materials, natural materials with the advantages of environmental protection, convenient for construction and low cost gradually have been appreciated by engineers. Experimental investigations will be conand constitutive model of wheat(or rice) hust-reinforced cohensive soil will be conducted in the project. Based on series of tests, including direct shear test, unconfined compressive strength test, triaxial test, we will study the physical and mechanical properties and deformation characteristics of the reinforced soil.By using scanning electron microscopy microstructure technology,the microstructure of reinforced soil speciments will be observed before and after loading in order to bring the interaction of reinforcment and soil particles to light. Then, we will construct the constitutive model's skeleton of the reinfoced soil on the basis of the aforementioned studies and determine the related parameters by tests. Finally, the rationality of the proposed constitutive model will be verified through numerical simulation and model test. The research project will promote the further development of natural material reinforced soil technology.

在各种加筋材料中，天然材料以其绿色环保、施工方便、成本低廉等特点，逐渐受到了工程界的青睐。本项目以农业废弃物（麦壳/稻壳）为加筋材料，加筋黏性土为研究对象，开展系列试验，包括直剪试验、无侧限抗压强度试验、三轴试验，研究其物理、力学特性及变形特性，同时采用电子显微镜扫描技术测试试样加载前后的微观结构，以此揭示筋材与土体颗粒间的相互作用机理，解释加筋土强度提高的原因；在上述研究的基础上，以其中加筋效果理想的加筋土为对象，提出该类加筋土的本构模型构架，并通过试验确定模型参数；最后，通过路基模型试验和数值模拟技术验证此本构模型的正确性。该项目的研究将推动天然材料加筋土技术的进一步发展。

为了研究麦秸秆加筋土在路基工程和边坡防护中的应用，本项目开展了一系列试验，包括三轴压缩试验、大型直剪试验、无侧限抗压强度试验和CT扫描试验，研究了麦秸秆加筋粉质粘土的加筋效果、应力应变特征以及破坏特征，试验结果表明：在土体中掺入麦秸秆，能有效控制土体的变形，增强土体的抗剪强度和抗压强度，加筋率为0.2%~0.3%、筋材长度为10~15时，加筋作用最强。之后在三轴压缩试验的基础上，借助BP神经网络构建了麦秸秆加筋土的本构模型。最后采用麦秸秆加筋挡墙和素土挡墙的模型试验比较，定性模拟了加筋土在工程中的应用，验证了麦秸秆加筋土的工程应用价值。