纤维加筋水泥土无侧限抗压强度及破坏形态分析

Unconfined Compressive Strength Test and Destructive Form Analysis of Fiber⁃Reinforced Cement Soil

以聚丙烯纤维、水泥和黏性土为原料制备水泥土固化材料,采用正交试验分析纤维长度、纤维体积掺量、水泥掺量和水灰比4个因素对纤维加筋水泥土无侧限抗压强度的影响,并结合单因素变量试验分析纤维加筋水泥土的破坏形态。结果表明,影响纤维加筋水泥土抗压强度的因素排序为水泥掺量>纤维体积掺量>水灰比>纤维长度;纤维体积掺量在0%~0.3%范围内时,同一水泥掺量的水泥土无侧限抗压强度随着纤维体积掺量的增加先增大后减小;适合黏性土的最佳配合比为纤维长度9 mm、纤维体积掺量0.2%、水泥掺量16%、水灰比0.4,按此配比制作的纤维加筋水泥土无侧限抗压强度平均值达到4.32 MPa,超过施工中常用加固土强度的设计要求,且较为经济;聚丙烯纤维能够增加水泥土的延性,减少脆性破坏,改善水泥土的工作性能。

Cement soil solidification materials were prepared using polypropylene fibers,cement,and cohesive soil as raw materials,effects of fiber length,fiber volume fraction,cement content,and water cement ratio on the unconfined compressive strength of fiber-reinforced cement soil analyzed via orthogonal experiments,and destructive form of fiber-reinforced cement soil studied through single factor variable experiments.The results indicate the following:the factors affecting the compressive strength of fiber-reinforced cement soil are ranked in descending order as cement content>fiber volume content>water cement ratio>fiber length;when the fiber volume fraction is between 0%to 0.3%,the unconfined compressive strength of cement soil with the same cement content increases first and then decreases with the increase of fiber volume fraction;the optimal mix ratio for cohesive soil is fiber length of 9 mm to fiber volume content of 0.2%to cement content of 16%to water cement ratio of 0.4.The average unconfined compressive strength of fiber-reinforced cement soil produced at this ratio reaches 4.32 MPa,which exceeds the design requirements for reinforced soil strength commonly used in construction at an more economical cost than otherwise;polypropylene fibers can increase the ductility of cement soil,reduce brittle failure,and improve the workability of cement soil.