贵州地区石灰改良膨胀土无侧限抗压强度的试验研究

Experiment study on unconfined compressive strength of lime stabilized expansive soil in Guizhou province

以贵州地区某工程的膨胀土为研究对象,通过室内试验,研究石灰掺入率、压实系数及养护龄期对改良土无侧限抗压强度的影响。试验结果表明:改良土无侧限抗压强度随着压实系数的增大而增大,随着龄期的增长而增大,随着石灰掺入率的增加先增大后减小,最佳掺灰率为9%。无侧限抗压强度影响因素的灰色关联度分析结果表明,压实系数对改良土无侧限抗压强度的影响最大,其次是养护龄期,而掺灰率的影响最小。改良土的应力应变关系曲线呈应变软化模型,试样的破坏模式为脆性破坏。本文的研究结果可为类似工程提供借鉴。

An experimental investigation was undertaken to study the effects of lime stabilized soil on the strength behavior of expansive soil.In the present investigation,a series of laboratory tests （unconfined compression tests）were conducted on lime stabilized expansive soil which was from Guizhou province.Lime contents,ran-ging from 3%,5%,7%,9%,to 1 1%of dry weight of expansive soil were used in the stabilized soil.In addi-tion,the stabilized soil was compressed at compacting factor of 0.90,0.92,and 0.95.Tests on expansive soils were conducted at different curing periods i.e.,7,14,and 28 days.The test results reveal that unconfined compressive strength （USC）increases significantly with the increase of the compacting factor and the curing peri-od.Also,the results show that USC of the treated expansive soil tend to increase with increasing lime content up to 9%,beyond which it slightly decreases.Grey correlation analysis which was about the factors of USC indi-cates that compacting factor is the most important factor affecting USC of the sample,followed by the curing peri-od,and lime content enhanced USC the least.The brittle failure occurs for all the samples of the lime treated ex-pansive soil,when the stress-strain relationship presents strain softening characteristics.The research results are of reference value to design and construction for other similar projects.