抗疏力固化剂改性黄土物理力学性质试验研究

Experimental Study on the Physical and Mechanical Properties of Loess Reinforced by Consolid System

研究目的:使用改性材料(固化剂)是黄土地基加固处理的常见方法,但传统改性材料存在一定问题,如石灰改性土的强度相对较低,且耐水性较差;水泥改性黄土的收缩性大,容易开裂,且会对环境造成一定的影响。因此,寻求环境友好、性能优良的土壤固化剂来解决传统改性材料存在的不足,对改性黄土具有重要意义。本文对抗疏力固化剂改性黄土进行试验研究,同时与水泥和石灰改性黄土进行对比分析,通过无侧限抗压强度、崩解及SEM等试验研究固化剂掺量和养护龄期对黄土强度、水稳性及微观结构的影响。研究结论:(1)抗疏力固化剂改性黄土的强度随着固化剂掺量和养护龄期的增加而增大,当养护龄期为28 d时,随着固化剂掺量的增加(1%~5%),抗疏力改性黄土的强度由55 kPa增长至95 kPa,其中5%抗疏力改性黄土的强度介于水泥改性黄土(370 kPa)和石灰改性黄土之间(71 kPa);(2)改性黄土的水稳系数和抗崩解性随着固化剂掺量的增加而不断提升,随着固化剂掺量的增加(1%~5%),抗疏力改性黄土的水稳系数由0.13提升至0.36,5%抗疏力改性黄土的水稳性介于石灰改性黄土(0)和水泥改性黄土(0.75)之间;(3)抗疏力固化剂显著提升了土体的斥水性;(4)随着固化剂掺量的增加(1%~5%),抗疏力改性黄土的渗透系数由0.63×10^(-6)cm/s降低至0.36×10^(-6)cm/s, 5%抗疏力改性黄土的渗透性介于石灰改性黄土(0.88×10^(-6)cm/s)和水泥改性黄土(0.32×10^(-6)cm/s)之间;(5)SEM图像显示,随着抗疏力固化剂掺量的提高,土体内部的大孔隙明显减少,土颗粒之间的连接更加紧密,分布更为均匀;(6)本研究成果可为黄土地区地基加固处理提供参考。

Research purposes:The use of modified materials(curing agent)is a common method of loess foundation reinforcement treatment,but there are certain problems with traditional modified materials,such as the lime-modified soil with relatively low strength and poor water resistance,cement-modified loess with large shrinkage,easy to crack,and certain impact on the environment.Therefore,it is important to seek environmentally friendly and high performance soil curing agents to solve the shortcomings of traditional modification materials to modify loess.This paper conducted an experimental study on the modification of loess by consoled system,and conducted a comparative analysis with cement and lime modified loess.The effects of curing agent dosing and curing age on the strength,water stability and microstructure of the loess were investigated by unconfined compressive strength,disintegration and SEM tests.Research conclusions:(1)The strength of the loess modified by consolid system increases with the increase of curing agent dosing and curing age.When the curing age is 28 d,the strength of the modified loess increases from 55 kPa to 95 kPa with the increase of curing agent dosing(1%~5%).The strength of the 5%modified loess is between cement-modified loess(370 kPa)and lime-modified loess(71 kPa).(2)The water stability coefficient and disintegration resistance of the modified loess increase with increasing amount of curing agent.With increasing amount of curing agent(1%~5%),the water stability coefficient of the modified loess increases from 0.13 to 0.36.The water stability of the 5%modified loess is between that of lime-modified loess(0)and cement-modified loess(0.75).(3)The consolid system significantly improves the water repellency of the soil.(4)With the increase of consolid system(1%~5%),the permeability coefficient of modified loess decreased from 0.63×10^(-6)cm/s to 0.36×10^(-6)cm/s.The permeability of 5%modified loess was between that of lime-modified loess(0.88×10^(-6)cm/s)and cement-modified loess(0.32×10^(-6)cm/s).(5)SEM images show that with the increase of curing agent dosing,the large pores inside the soil are significantly reduced,and the connection between soil particles is tighter and more uniformly distributed.(6)The research results can provide a reference for foundation reinforcement treatment in loess areas.