石灰改性淤泥的抗压和抗剪强度试验研究

对未改性淤泥和石灰改性淤泥进行无侧限抗压强度试验,得到了长期养护90 d和360 d试样的应力应变关系、抗压强度、变形模量和破坏应变。通过固结排水直接剪切试验,得到淤泥固化前后的剪切应力位移关系、凝聚力和内摩擦角。结果表明:石灰的掺入使试样破坏应变明显减小,无侧限抗压强度和变形模量显著增加;石灰掺量达到某种程度后,继续添加石灰并不能改善土体力学性质,反而会引起劣化效果;抗压强度与变形模量之间服从线性关系,抗压强度与破坏应变之间服从幂函数关系;石灰掺量和法向压力变化会诱发试样剪切应力位移曲线发生变化;石灰可有效提高淤泥试样的凝聚力,但对内摩擦角并无显著影响。

Experimental study on compressive and shear strength of lime-modified sludge

For untreated and lime-modified sludge, the unconfined compressive strength tests were carried out to obtain the stress-strain relationship, compressive strength, deformation modulus and failure strain after long curing of 90d and 360d. Through consolidated drained direct shear tests, the relationship between shear stress and shear displacement, the cohesion and internal friction angle of sludge before and after the consolidation were obtained. The results show that the addition of lime obvi-ously reduces the failure strain and increases the compressive strength and deformation modulus. When the lime content goes up to a certain amount, further addition of lime cannot improve the mechanical performance of lime-modified soils, but deteriorate its mechanical property. A linear model can describe the relationship between compressive strength and deformation modulus, while the power function depicts well the correlation between compressive strength and failure strain. The shear stress and shear displacement curves are closely related to normal consolidation stress and lime amount. The incorporation of lime can effectively enhance the cohesion of sludge samples, but it has a negligible influence on the internal friction angle.