污水环境对水泥土渗透性能影响的试验研究

现多数水泥土防渗工程都间接或直接的与地下腐蚀性介质环境接触，会导致水泥土防渗性能的降低甚至失效。因此，通过室内模拟试验，设计了不同的水泥掺入比，进行了在污水和清水环境下水泥土的渗透性能试验，研究了在不同龄期下水泥土的渗透系数变化规律，并同时分析了渗透后水泥土中离子浓度的变化规律。试验结果表明，在清水环境下，随着龄期的增长，水泥土的渗透系数逐步减小，60 d后随着龄期的增加，水泥土渗透系数减小的程度越来越缓慢；在污水养护条件下，龄期在60 d之前，水泥土渗透系数逐步减小，龄期在60 d之后，由于水泥土被侵蚀，致使水泥土随着龄期的增加，水泥土的渗透系数逐步增大；无论是清水还是污水环境，随着水泥掺量的增大，其渗透系数均逐步降低；在污水环境中，随着龄期的增加，其水泥土中的Ca2+，Mg2+，Cl?， 浓度均逐步增大，而清水环境中Mg2+，Cl?， 浓度均逐步减小。其研究成果可为水泥土防渗工程的抗渗性和耐久性设计和应用提供技术参数，具有重要的工程意义。

Effect of sewage environment on permeability of cemented soil

Cemented soil in anti-seepage engineering usually directly or indirectly encounters underground corrosive media environment, which may lead to decrease or even failure in impermeability. For this purpose, the permeability tests are conducted on the cemented soil with different cement ratios under the sewage and clean water conditions, respectively. The effects of curing ages on the permeability of cemented soil are investigated, and the evolutions of ion concentration in cemented soil after permeating are also analyzed. The result shows that for the samples soaked under clean water curing condition, their permeabilities decrease gradually with increasing curing age, and this decreasing rate becomes more slowly when the curing age exceeds sixty days. For the specimens soaked under sewage curing condition, their variations of permeabilities are similar with those of specimens with the curing age less than sixty days under clean water curing condition. However, an increase in the permeability is observed when the curing age exceeds sixty days. This phenomenon is attributed to the erosion effects of sewage on cemented soil. Under both clean water and sewage curing conditions, the permeability decreases gradually with the increase of cement content. With the increasing of curing age, the concentrations of Ca2+, Mg2+, Cl? and SO42? in cemented soil gradually increase under sewage curing condition, whereas the concentrations of Mg2+, Cl?, SO42? gradually decrease under clean water curing condition. The research results can provide technical parameters for the impermeability and durability design of cemented soil in anti-seepage engineering, which have an important engineering significance.