微生物—活性氧化镁固化盐渍土强度变化规律研究

Study on strength characteristics of microbial-reactive magnesia oxide solidified saline soil

利用微生物—活性氧化镁固化技术改良滨海细粒氯盐盐渍土,通过不同氧化镁掺量条件下固化盐渍土的无侧限抗压强度试验、直剪试验及水稳性试验,探究此方法固化盐渍土的强度变化规律及改良效果,试验结果表明:微生物作用可明显促进活性氧化镁反应,加速固化盐渍土;活性氧化镁掺量增加,固化盐渍土的无侧限抗压强度和抗剪强度均随之增大,20%氧化镁掺量的固化盐渍土的抗压强度和抗剪强度(法向应力为100kPa时)分别是未改良盐渍土的8.18倍和8.21倍;黏聚力随着活性氧化镁掺量的增加明显增大,而内摩擦角呈现先增大后减小的趋势;活性氧化镁掺量增加,固化后盐渍土的水稳系数也增大,可明显改善盐渍土的水稳性。

The microbial-reactive magnesium oxide solidifying technique is used to improve the coastal fine-grained chloride saline soil.Through the UCS tests,direct shear tests and water stability tests for the solidified saline soil under different magnesium oxide contents,the change rules of the strength of the solidified saline soil and the improvement effects of this method are explored.The test results show that:the microbial action can obviously promote the reaction of active magnesium oxide and accelerate the solidification of saline soil.The UCS and shear strength of the solidified saline soil will increase with the increase of active magnesium oxide content.The UCS and shear strength(at a normal stress of 100kPa)of the solidified saline soil with 20%magnesium oxide content are 8.18 times and 8.21 times of that without improvement,respectively.The cohesion increases obviously with the increase of active magnesium oxide content,while the internal friction angle increases firstly and then decreases.With the increase of active magnesium oxide content,the water stability coefficient of the solidified saline soil also increases,which can obviously improve the water stability of the saline soil.