水泥固化软土抗拉特性研究

Research on tensile characteristics of cement-treated soft soil

为探究固化土的拉伸破坏问题,利用研制的单轴拉伸试验仪研究水泥固化不同软土的抗拉特性;基于抗拉强度随灰水比(水泥与水的质量之比)和龄期的变化规律,建立双曲线形式的抗拉强度-龄期关系式。研究结果表明:抗拉强度、拉伸模量随水泥土的灰水比和龄期增加而增大;表征材料韧性的断裂能随龄期增加而增大,胶州湾黏土固化土断裂能随灰水比先增大后减小,而东营港粉土固化土断裂能随灰水比持续增大;水泥土的抗拉强度与无侧限抗压强度呈线性关系,其拉压比可取0.15;与其他学者的试验数据对比,所提公式的抗拉强度计算值与试验结果较吻合,能在一定程度上反映水泥固化软土抗拉强度随龄期的变化规律。

In order to explore the tensile failure properties of solidified soil,the developed uniaxial tensile tester was conducted to investigate the tensile characteristics of cement-treated soft soil.Based on the law whereby the tensile strength of cement-treated soil increases with the curing time and cement-water ratio(mass ratio of cement to water),a hyperbolic formula was established,with which the relationship between the tensile strength of cement-treated soft soil and curing time was obtained.The results show that the tensile strength,tensile modulus increase with the cement-water ratio and curing time and the fracture energy characterizing the toughness of materials increases with the curing time.The fracture energy of cement-treated Jiaozhou Bay clay increases at first and then decreases with the cement-water ratio,while the fracture energy of cement-treated Dongying Port silt continues to increase with the cement-water ratio.The tensile strength of cement-treated soil has a linear relationship with the unconfined compressive strength,and the tension-compression ratio can be adopted as 0.15.The calculated values of tensile strength obtained by the proposed formula are consistent with the experimental results,which can basically reflect the change law of the tensile strength of cement-treated soft soil.