水泥掺量和龄期对渠道水泥土垫层抗拉强度的影响规律

The Effect of Cement Content and Curing Age on the Tensile Strength of Cement Soil Cushion under a Channel

水泥土作为一种土体加固改良技术,已得到广泛应用,但目前对影响水泥土抗裂能力的抗拉强度研究相对较少。以新疆伊犁一水电站引水渠道防渗垫层工程为对象,开展了伊犁黄土中掺水泥形成的水泥土单轴拉伸试验,并与素土抗拉强度对比,探讨水泥掺量、养护龄期对水泥土抗拉强度、极限拉应变的影响规律,提出了综合考虑水泥掺量、养护龄期的水泥土抗拉强度计算公式。同时,开展了水泥土的渗透试验,研究了水泥土的渗透特性规律。试验发现,水泥土的抗拉强度随水泥掺量的增加和养护龄期的增长而增大,且成型后7~14 d抗拉强度增大较为明显;水泥掺量为10%时水泥土的抗拉强度随水泥掺量的增大而增大的比率较大,大于10%后则增量趋缓;水泥土极限拉应变集中在1.6%~3.7%;养护条件对水泥土的抗渗能力影响很大。

Cement soil has been widely used as a kind of ground treatment technology. However,there are relatively few studies on the tensile strength that affects the crack resistance of cement soil. In this paper,the anti-seepage cushion of a hydropower station in Yili is studied by the uniaxial tensile test of cement soil. And the tensile strength of cement soil is compared with the tensile strength of unimproved soil.Additionally the effect of cement content and curing age on tensile strength and ultimate tensile strain of cement soil is investigated. And a formula for calculating the tensile strength of cement soil considering the amount of cement content and the curing age is proposed.Meanwhile,the infiltration test is carried out to study the infiltration characteristics of cement soil. Tests have found that the tensile strength of cement soil increases with the increase in cement content and growth of curing age. And the increase in tensile strength is obvious in 7 ~ 14 d. When the cement content is 10%,the tensile strength of cement soil increases rapidly with the increase in the cement content,when the cement content is more than 10%,the increment gradually decreases. And cement soil ultimate tensile strain varies between 1.6% and 3.7%.In the meantime,conservation conditions have a great influence on the impermeability of cement soil.