水泥砂浆固化土抗压强度特性试验

Experimental study of compressive strength properties of soils stabilized by cement mortar

为论证水泥砂浆固化土工程应用的可行性,通过设置不同掺砂量、含水率、砂料粒径和养护龄期条件,对水泥砂浆固化土进行无侧限抗压强度试验.试验结果表明:(a)掺砂可提高水泥砂浆固化土的抗压强度,尤其是早期强度.一定水泥掺入比条件下,当掺砂量处于最优掺砂率(10%左右)时水泥砂浆固化土的强度特性改善幅度最大,掺砂量超过最优掺砂率后水泥砂浆固化土的抗压强度无显著提高.(b)水泥砂浆固化土的抗压强度随原料土含水率的增加而减小,当原料土的含水率较低或养护龄期较短时,水泥砂浆固化土的抗压强度下降幅度均较大,当含水率较高时水泥土掺砂难以达到预期的固化效果.(c)砂料粒径变化对水泥砂浆固化土的抗压强度影响较小,水泥砂浆固化土强度随着粒径的增大略有提高;砂料粒径变化对水泥砂浆固化土变形系数的影响较大,两者近似成正比关系,在实际工程中无需对砂料进行筛分而直接运用即可获得较好的处理效果.(d)水泥砂浆固化土无侧限抗压强度试验的破坏模式多为脆性张裂破坏和塑性剪切破坏.随着养护龄期的延长以及掺砂量的增加,脆性张裂破坏更为显著.

In order to prove the feasibility of soils stabilized by cement mortar,a series of unconfined compressive strength tests were conducted to study the effects of sand content,water content,sand grain size,and curing age.The results show the following：（a） Blending sand can improve the compressive strength of stabilized soils,especially the early strength.The characteristics of strength of the stabilized soil were greatly improved based on a certain cement ratio when the sand content was optimal（about 10%）.The compressive strength had no significant increase when the sand content exceeded the optimal value.（b） The compressive strength of the stabilized soil decreased with the increase of the water content of raw soil.When there was a low water content of raw soil and a short curing period,the compressive strength decreased significantly.When there was a high water content of raw soil,it was difficult to achieve the desired curing effect.（c） The change of the sand grain size had little impact on the compressive strength of the stabilized soil： the strength slightly increased with the sand grain size.The change of the sand grain size had a significant impact on the deformation coefficient of the stabilized soil,and there was an approximate direct proportional relationship between them.Therefore,using sands directly without sieving in practical projects could produce good results.（d） The failure modes of the unconfined compressive strength tests of the stabilized soil were mainly characterized by brittle tensile fractures and plastic shear fractures,of which the brittle tensile fractures were more significant with the prolonging of curing age and the increase of sand content.