下穿越工程施工微扰动评价指标试验研究

 为控制下穿越工程施工对建筑密集城区的扰动度，确保将施工对环境影响控制在微扰动的范围之内，急需建立下穿越工程施工微扰动的评价指标，并对不同应力路径下微扰动指标的变化规律进行研究。从应力扰动和应变扰动2个方面入手，选取土体剪切模量、孔隙水压力、临界应力状态面指标作为土体微扰动评价主要指标，通过室内试验，获取下穿越工程施工中不同应力路径下原状土受扰动后的模量、孔压、应力与应变的关系曲线，定量分析研究下穿越工程施工扰动引起的环境土体中应力、应变状态变化。研究结果表明，土的剪切模量在很小的应变范围内随应变的增大急剧减小，但不同应力路径下剪切模量的变化幅度不同；微小的应变改变即可引起孔隙水压力的变化；此外，根据土的破坏面与扰动度的定义，可以界定符合微扰动控制要求的临界应力状态面。

EXPERIMENTAL STUDY OF INDICES FOR EVALUATING SMALL DISTURBANCE IN UNDERGROUND-CROSSING CONSTRUCTION

In order to control the soil disturbance caused by construction passing beneath highly dense building districts and to ensure the construction influence within small disturbance domain,the determination of indices for evaluating small disturbance and investigation on their variations under different stress paths during underground-crossing construction have become crucial issues.From the perspectives of stress disturbance and strain disturbance,the shear modulus,pore water pressure and critical stress state...