不同改性材料改良膨胀土无侧限抗压强度的比较试验研究

A Comparative Study of Different Modified Materials Improving the Unconfined Compressive Strength of Expansive Soil

无侧限抗压强度是反映土体物理力学特性的重要参数指标之一,结合湖北荆门地区某公路路段的膨胀土,进行了水泥、石灰、粉煤灰改良膨胀土的无侧限抗压强度试验,研究表明:水泥、石灰、粉煤灰均可以显著提高膨胀土的无侧限抗压强度;但是这些以化学改良为主的材料,在没有经过养护时,改性土的强度增加不明显;养护7d后,改性土的强度会显著增大;粉煤灰改良膨胀土无侧限抗压强度与其掺量之间有良好的对数关系,水泥、石灰改良膨胀土的无侧限抗压强度与其掺量之间均有良好的多项式关系,综合考虑各方面因素,确定石灰是最优方案,且在石灰掺量为7%时,改良效果最佳.

Unconfined compressive strength is the reflection of the physical and mechanical properties of soil and is one of important parameters. This paper carries the tests of cement,lime, fly ash improving the uncon- fined compressive strength of the expansive soil of a section of a highway in Jingmen region. The study shows that cement,lime or fly ash can significantly improve the unconfined compressive strength of the expansive soil, but these chemically modified materials, when without curing, can not obviously increase the strength of modified soil ,and when with 7d curing, the strength of modified soil is significantly increased. Fly expansive soil unconfined compressive strength and its dosage has a good logarithmic relationship. Cement or lime ex- pansive soil unconfined strength and its dosage has a polynomial relationship. The comprehensive considera- tion of various factors determines that lime is optimal,and when lime content is 7 %, the effect is the best.