填海作用对海积软土的抗剪强度影响试验研究

Experimental analysis on coastal reclamation impact on shear strength of marine soft soil

以钦州港临海园区和防城港企沙工业园填海场地海积软土为研究对象,分析了填海场地海积软土赋存环境要素的变化规律。采用机制模拟技术装置,对海积软土的孔隙水离子化学组分浓度和上覆填海层厚度发生变化的情况进行了人工模拟制样,获得了"印记"了赋存环境要素的人工软土样品,并对人工软土样品进行了直剪试验。结果表明:填海层对海积软土层的附加荷载应力、水力联系变化、水化学场变化三大赋存环境要素可采用"一种土的浸泡荷载联动装置"进行模拟;随着填海层附加荷载应力的增大,人工软土样的粘聚力c和内摩擦角φ随之增大;随着浸泡液不同离子成分浓度变化,对人工软土样的粘聚力c和内摩擦角φ影响效果不一,随着离子浓度的增加,Ca2+比Mg2+对抗剪强度指标的影响大;填海层附加荷载应力与浸泡液离子组分双因素同时作用下,对土样的抗剪强度指标存在相互耦合效应,其耦合效应对黏聚力影响明显,对内摩擦角影响较小。

The variation of the environmental factors of marine soft soil in industry zones of Qinzhou Port and Fangcheng Port was analyzed.The soil soaking load linkage is a self-developed device for mechanism simulation,used to examine the environmental factors of marine soft soil when the thickness of coastal reclamation layer and concentration of chemical constituents of pore water ions changed.The soft soilsamples were obtained artificially.Direct shear tests of threse artificial soft soil samples were carried out.The test results showed that cohesive force c and internal friction angleφof artificial soft soil samples changed with calcium ion larger than magnesium ion when concentration of calcium ion or magnesium ion increased.There is certain coupling effect between the additional load stress of coastal reclamation layer and ion concentration of soak liquid for the shear strength indexes of the soil.However,the coupling effect of cohesive force is obvious while that of internal friction angle is less significant.