河道淤泥气泡混合土的力学性质及破坏机理研究

Foamed light soil with river sludge is a sort of mixed material with river sludge. It can be used for soft ground treatment, high fill project, backfill and so on as new soil material with favorable effectiveness or wide future. Since foamed light soil with river sludge shows structural mechanism of high water content, big pore and multiphase, the mechanical properties and failure mechanism related with engineering properties of foamed light soil are different from general soil materials. In this project, researches will focus on mechanical properties and failure mechanism of foamed light soil with river sludge, such as common physical-mechanical properties, strength and deformation properties under different loading or environment conditions and influential factors or relationship. Both theoretical methods and experimental methods, as well as numerical simulation will be adopted during researching. The physical-mechanical properties of foamed light soil will be researched with experimental methods based on the regional distribution features of river sludge. In view of the multiphase and porosity of foamed light soil, the relationships between strength or deformation of foamed light soil and microscopic pore distribution property will be explored with microscopic analytical method or numerical simulation. On account of big pore structural mechanism of foamed light soil, stress strain fields under static or dynamic loading will be simulated with three-dimensional finite element numerical model. By means of above approaches, the strength and failure mechanisms of foamed light soil with river sludge could be comprehended.

河道淤泥气泡混合土是一种以河道淤泥为基质材料的混合型轻质土工材料，在软基处理、高填土工程、台背或地下回填处理等领域显示良好的效果及广泛的应用前景。由于以淤泥为原料土的气泡混合土具有明显的高含水、大孔隙及多相性等特征，其与工程性质相关的力学性质及破坏机理不同于常见的土工材料。本课题关于河道淤泥气泡混合土力学性质及破坏机理的研究内容主要包括利用试验研究、理论分析及模拟计算等方法对河道淤泥气泡混合土的基本物理力学性质、在不同荷载或环境条件下的强度、变形特性，影响因素及变化规律进行系统的研究。根据河道淤泥的区域分布特征，利用试验方法研究气泡混合土的物理力学性质，根据气泡混合土的多相性及多孔性构造特征，研究微观孔隙分布特征及对气泡混合土强度、变形性质的影响，根据气泡混合土的大孔隙构造特征建立三维有限元数值计算模型，考虑加载特征分析在静、动荷载作用下的应力应变场，揭示气泡混合土的强度发挥和破。

基于资源有效利用及环境保护目的，提高河道淤泥综合有效利用效率是目前亟待解决的社会及工程问题。本项目以河道淤泥综合有效利用为目的，开展河道淤泥气泡混合土物理力学性质及破坏机理的试验研究及理论分析，为河道淤泥的工程应用建立基础。气泡混合土作为一种新型土工材料，其工程力学性质受多种因素影响，荷载作用下破坏机理复杂。气泡质量及土中气泡的空间分布特征是影响气泡混合土的主要因素，通过配合优化试验，配制成了成泡质量良好、稳定性较高的发泡剂，为制备高品质气泡混合土提供了基础。利用试验考察研究了河道淤泥气泡混合土在静、动荷载作用下的力学性质，试验结果表明在荷载作用下河道淤泥气泡混合土既保持了一般轻质土的基本特征，又具备常规土工材料的强度及变形特性，作为一种新型土工材料既能满足工程性能要求，又能显著提高河道淤泥的有效利用效率。利用孔结构微观分析及数值模拟分析方法研究了荷载作用下河道淤泥气泡混合土的强度发挥及破坏机理，为建立相应的分析模型及提高混合土质量提供理论基础。基于耐久性要求，重点研究考察了在酸性物质作用下河道淤泥气泡混合土的耐久性问题，结果表明在酸性物质作用下混合土具备一定的耐久能力。