引洮7~#隧洞含水疏松砂岩地层冻结法施工数值模拟

为探究含水疏松砂岩地层引水隧洞冻结施工中冻土帷幕的形成过程及力学特性,对引水隧洞的冻结施工及开挖过程进行三维数值模拟。研究了冻土帷幕的温度场、应力及位移的分布,计算出冻土帷幕完全形成所需的时间及其压、拉、剪应力极值并确定极值发生的位置。结合现场监测数据,分析了冻结过程中冻土的温度变化规律及冻土帷幕的形成机理,最后提出了相应的措施及建议。

Numerical simulation on freezing construction of No.7 tunnel of Water Supply Project of Transferring Water from Taohe River through aquiferous and unconsolidated sandstone strata

In order to study the forming process and mechanical properties of the frozen-soil curtain during the freezing construction of the diversion tunnel through aquiferous and unconsolidated sandstone strata， a 3-D numerical simulation is made on the process of freezing construction and excavation of the diversion tunnel. The distributions of the temperature fields， stresses and displacements of the frozen-soil curtain are studied， and then the time and the ultimate values of its tensile stress， compressive stress and shear stress necessary for the full formation of the frozen-soil curtain are calculated， while the locations the ultimate values occur are determined as well. Combined with the in situ monitoring data， the temperature changing law of the frozen-soil and the forming mechanism of the frozen-soil curtain are analyzed. At last， some corresponding measures and suggestions are put forward.