土工格室+碎石桩双向增强复合地基沉降计算方法研究

土工格室+碎石桩双向增强复合地基作为一种新型的软基处治方法，因其良好的工作性能获得了工程界的青睐，但该处治方法的沉降计算方法尚欠成熟。本研究拟结合目前已有研究成果，进行土工格室+碎石桩双向增强复合地基室内模型试验，深入探讨其荷载传递机理、固结特性及变形机理；在此基础上，选用不同的桩、土和筋材材料本构关系，建立桩-土-筋材相互作用的控制方程，并引入无单元法进行求解，实现复合地基的弹塑性大变形数值模拟。最后，基于土工格室+碎石桩双向增强复合地基的变形机理分析，建立其沉降计算模型，并基于最小势能原理，建立桩-土-筋材体系的能量平衡方程，引入适宜的位移函数进行求解，从而提出一种可应用于实际工程的土工格室+碎石桩双向增强复合地基沉降计算方法。

As a new soft foundation treatment method, the composite foundation bidirectionally reinforced by geocell and gravel columns is favored for civil engineers for its better service behavior. However, the settlement calculation method of the composite foundation remains immature. The model tests of composite foundation bidirectionally reinforced by geocell and gravel columns are conducted in this study based on the current research. The load transfer mechanism ,consolidation and deformation characteristcs of the composite foudantion are deeply discussed. Then, the basic equations of gravel column, soil and reinforcement interaction are established with the different stress-strain models of gravel column, soil and reinforcement chosen. The equations are solved by the element-free method and the great elastic-plastic deformation of composite foundation is numerically simulated. Lastly, the deformation mechanism of composite foundation bidirectionally reinforced by geocell and gravel columns is analyzed and the settlement calculation model is presented. Based on the principle of minimum potential energy, the basic energy equations of gravel column, soil and reinforcement interaction are established and solved by an appropriate displacement function. Then a simplified settlement calculation method of composite foundation bidirectionally reinforced by geocell and gravel columns applied to practical engineering is obtained through the above studies.