修正Terzaghi理论在吹填土固结计算中的应用

经典Terzaghi一维固结理论在小变形线弹性固结沉降计算中广泛应用,固结系数、压缩性、渗透性等固结参数保持为常量,但直接应用于沉降量超过50%的吹填土固结沉降会引起不可忽视的坐标误差,导致较大的预测误差,存在应用上的局限性。修正Terzaghi理论计算方法,根据有限应变理论将吹填土大变形固结沉降分段表达,同时修正应变步长上固结参数,满足经典固结理论中小变形、线弹性假定条件。通过土体渗透系数、体积压缩系数与孔隙比间拟幂次函数关系表达吹填土体非线性本构关系,固结系数不再保持为常量,而在固结过程连续变化。修正Terzaghi固结理论分段计算方法,在确定沉降应变步长内固结系数为常量,计算相应时间步长,修正土体固结系数及固结参数后进行下一应变步长计算,累加沉降量与时间步长得到土体时间维度上的大变形固结曲线。修正Terzaghi固结理论满足线弹性小变形基本假定,反映出软土固结沉降中非线性特点,计算预测结果与实测值符合良好,将经典一维固结理论推广应用到吹填土大变形固结领域。

Application of Modified Terzaghi Consolidation Theory in Hydraulic Fill Soil Consolidation Evaluation

Application of classical one-dimensional Terzaghi consolidation theory is widely in elastic small strain consolidation with assumption that consolidation coefficient, permeability keep constant. But non-neglected prediction errors exist during the application and compressibility Terzaghi theory in hydraulic fill consolidation as the settlement exceeds 50% will lead to great coordinate errors and a using limit. According to finite strain consolidation theory, modified Terzaghi theory calculates consolidation and modifies consolidation parameters on each strain step which will meet the agreement of small strain and elasticity. Through the nonlinear quasi-power functional relationships between permeability, compressibility and void ratio to express consolidation coefficient, consolidation coefficient the trend isn＇t constant, and keeps changing in consolidation. It is reasonable to assume the variable consolidation coefficient is constant in a finite strain step （1% -5% ） to apply modified Terzaghi consolidation theory. After obtaining the related time step, modify the consolidation parameters such as consolidation coefficient, initial void ratio to calculate the time step at next finite strain step. Cumulate all the finite strain step settlement and time, consolidation curves can be got. Modified Terzaghi theory can meet the basic assumptions and reflect the nonlinear characteristic in consolidation, and the prediction results show a well agreement to the measured data. Modified Terzaghi theory can be introduced into large strain consolidation area.