土体含盐量对长江口地区软黏土特性的影响

长江口地区广泛分布的软黏土是一种不良地质土,具有压缩性高、强度低、灵敏度高的特点.土体含盐量在不同的季节下会受河流、潮汐、降雨等因素的影响会发生波动.对长江口沿岸软黏土进行采样并测定其含盐量,然后通过对原状样进行直剪试验、侧限压缩试验、渗透试验,得到了土体含盐量对软黏土抗剪特性、压缩特性、渗透特性的影响规律.结果表明:原状软黏土含盐量在0.5％ ～1.1％时,土体含盐量越高,土体的抗剪强度越高、土体压缩性越低、渗透性越强.根据对渗滤过的原状土进行试验对比分析,黏土颗粒中的盐分、孔隙水中的盐分共同影响软黏土的特性;黏土颗粒中的盐分对软黏土特性的影响更大.最后通过压汞试验得到了含盐软黏土的孔隙分布特征.长江口沿岸地区土体冬季的力学性能较差,应该更加注重冬季工程地质灾害的防治.

Effect of soil salinity on the characteristics of soft clay in the Yangtze Estuary

The soft clay widely distributed in the Yangtze Estuary is a bad geological soil. It has the characteristics of high compressibility, low strength and high sensitivity. The salt content of the soil fluctuates under the influence of rivers, tides, rainfall and other factors in different seasons, which causes a large change in the characteristics of soft clay. The soft clay along the Yangtze River estuary was sampled and its salt content was determined, and it passed the direct shear test, lateral compression test and penetration test of the original sample. The influence law of the soil salt content on the shear property, compression property and permeability property of the soft clay is obtained; the results show that within the range of the salt content of the original soft clay, the higher the salt content of the soil, the higher the salt content of the soil. The lower the friction angle and cohesion, the stronger the soil compressibility. According to the test on the intact soil obtained by infiltration, the salt in the clay particles and the salt in the pore water affect the characteristics of the soft clay. The salt content in clay particles has a greater influence on the characteristics of soft clay. According to the test results, the physical change characteristics of soft clay throughout the year can be predicted to make up for the deficiencies caused by the site survey results, thereby improving the safety of engineering construction. The soil body along the Yangtze River estuary has poor mechanical properties in winter, and more attention should be paid to the prevention of engineering geological disasters in winter.