广西贺州红黏土的工程性质研究

Research on Engineering Properties of Lateritic Clay in Hezhou

为了研究贺州地区红黏土的工程性质,通过岩土试验对其物理性质和力学性质进行分析。结果表明：贺州红黏土天然孔隙比高于常见的黏性土,土体黏粒含量较高,液限高,膨胀性弱,属于中压缩性土,渗透系数在0.1m/d^0.5m/d之间,最优含水量为25% ,最大干密度为2.03g/cm^3;裂缝以竖向为主,以横向为辅,竖向裂缝宽度为2~5.6 mm,横向裂缝宽度为0.6~5.9 mm;土体的标贯击数在8.5~15击之间,对应的承载力特征值为233kPa^317.36kPa;随着含水率的增大,抗剪强度逐渐增强（含水率到达24% 时最强）,无侧限抗压强度也逐步增强（含水率达27% 时最强）;土-水特征曲线含有突变点,吸力控制值小于21.82MPa时曲线趋于平缓,吸湿与脱湿段间存在一定的滞回效应;吸力达367.54 MPa时,吸湿段或脱湿段土样最终含水率几乎接近于0% 。

In order to study the engineering properties of lateritic clay in Hezhou region, the physical properties and mechanical properties are analyzed by geotechnical tests. The results show that： compared with the average cohesive soil in Hezhou, lateritic clay has higher natural void ratio, higher clay content, higher liquid limit, and weak expansibility; it belongs to the medium compressed soil, and the permeation coefficient is between 0.1 m/d and 0.5 m/d, the optimum water content is 25%, and the maximum dry density is 2.03 g/cm2; the fractures are mainly vertical, supplemented by transverse direction, and the vertical crack width is about 2~5.6 ram, the horizontal crack width is about 0.6~5.9 mm; the standard number of soils is between 8.5 and 15, and the corresponding bearing capacity is 233 kPa^317.36 kPa; with the increase of water content, the shear strength gradually increases and becomes the strongest when the moisture content reaches to 24 0/60, and unconfined compressive strength is also gradually enhances and becomes the strongest when the moisture content reaches to 27%; the soil-water characteristic curve contains a catastrophe point, the suction control value is less than 21.82 MPa when the curve tends to be gentle, and there is a certain hysteresis between the moisture absorption and dehumidification effect; and the final moisture content of the soil in the wet or dehumidified section is almost close to zero when the suction reaches 367.54 MPa.