冻融循环下灰土垫层渗透性和强度试验研究

Test Study on the Permeability and Strength Variation of Lime Soil Bedding Under Freezing and Thawing Cycles

针对西安大明宫国家遗址公园御道工程透水混凝土灰土垫层的设计要求,分别进行了冻融循环10次下灰土35d龄期时的单轴抗压强度试验、渗透性试验和快速直接剪切试验。结果表明:若忽略试样含水量的影响,灰土快速直接剪切试验抗剪强度随冻融循环次数增加而呈指数型衰减并较快趋于稳定,其拟合曲线和公式均与实测数据吻合良好,但是,其抗剪强度指标黏聚力和内摩擦角的规律较差,与两次拟合误差有关;灰土渗透系数随冻融循环次数增加呈指数型衰减,其拟合公式和曲线与实测数据吻合较好;含水量为24%～26%时,该石灰掺量(干石灰占干土料百分比为15%)下处理马兰黄土得到的35d龄期单轴抗压强度在冻融循环下的稳定性较好。

Based on the design parameters of lime soil bedding under permeable concrete in imperial road engineering in Xi＇an Daminggong Palace National Heritage Park, the uniaxial compressive test, permeability test and fast direct shearing test of lime soil on age 35d are accomplished under ten freezing and thawing cycles. The results show that the fast direct shearing strength decrease exponentially with the number of freezing and thawing cycles without consideration of moisture content, and the fitting curve and equation is according with the measured values well. However, the rule between of strength parameter （such as cohesive force and internal friction angle） and freezing and thawing cycles is not obvious with the inaccuracy of two fitting process. Furthermore, the coefficient of permeability decreases exponentially with the number of freezing and thawing cycles, and the fitting curve and equation is according with the measured values well, which prove that the uniaxial compressive strength on age 35d of lime soil treated with lime of dry mass ratio 15% is stable under freezing and thawing cycles with the water content of 24% to 26%.