掺矿粉的水泥土力学性能试验研究

Experimental Study on Mechanical Properties of Soil-cement Mixed with Slag Powder

水泥土是基坑止水帷幕的基本材料,因此必须具有一定的强度和抗渗性能,而矿粉的掺入能够改善水泥土的性能,因此,研究矿粉掺量和龄期对水泥土性能的影响对止水帷幕施工有较大的参考价值。本文选取苏州具有代表性的粉砂夹粉土,按7种不同配合比加入水泥和矿粉,对水泥矿粉土进行室内抗压强度和渗透试验,采用不同拟合函数对水泥矿粉土实测强度值进行数学拟合。研究表明:在一定固化剂总掺入比(30%)和水灰比(1.5)条件下,水泥矿粉土强度随龄期增加而增加、随矿粉掺入比增加而先增加后减小,矿粉掺入比为15%时水泥矿粉土强度值最大,水泥矿粉土强度大于水泥土强度;水泥矿粉土渗透系数小于水泥土渗透系数,矿粉掺入比为15%时渗透系数较小;采用多项式拟合水泥矿粉土实测值,拟合精度较高。综上,可以在止水帷幕施工中掺入适量的矿粉增强墙体的性能。

Cement-soil is the basic material of foundation pit water-proof curtain,so it must have certain strength and impermeability,and the addition of mineral powder can improve the performance of cement-soil.Therefore,the study of the influence of mineral powder content and age on the performance of cement-soil has great reference value for the construction of water-proof curtain.In this paper,representative samples of silty sand with silt in Suzhou are selected,and then cement and slag powder are added according to 7 different proportions.The indoor compressive strength and permeability tests of the slag powder soil-cement are carried out.The measured strength values are fitted mathematically with different fitting functions.The results are as following:under the condition of a fixed amount of stabilizer(30%)and water cement ratio(1.5),the strength of slag powder soil-cement increases with age;the strength increases first and then decreases with the increase of the ratio of slag powder,and reaches the maximum when the ratio of slag powder is 15%;the strength of slag powder soil-cement is greater than that of soil-cement without slag powder,while the permeability coefficient is smaller;when the ratio of slag powder is 15%,the permeability coefficient is rather small;the polynomial fitting method is used to fit the measured value of slag powder soil-cement,and the fitting accuracy is satisfactory.In conclusion,the performance of the wall can be enhanced by adding appropriate amount of mineral powder in the construction of water-proof curtain.