真空预压法处理火山灰质淤泥试验研究与应用

Experimental Study and Application Case of Improving Volcanic Ash Soft Clay by Vacuum Consolidation Method

通过严谨的室内试验、室外试验以及严格控制质量的大面积实施过程,确保真空预压在火山灰质淤泥地质条件下的成功应用。该火山灰质淤泥的含水率显著高于一般黏性土淤泥,但是85%以上的土颗粒为粉土颗粒,力学指标在真空预压处理后得到显著提高。火山喷发时的喷发物快速冷却形成在颗粒内部含有大量孔隙的粉土颗粒,这些颗粒内部的孔隙可容纳大量水从而导致其含水率显著高于一般黏性土淤泥,但是这些颗粒内部水分对土颗粒之间的力学行为不产生影响,所以该火山灰质淤泥的力学指标在固结排水过程中获得的提高仍然符合预期。

By doing rigorous indoor trial test,outdoor trial test and high quality controlled construction, vacuum consolidation method is successfully applied for improving volcanic ash soft clay in this case.The water content of encountered volcanic ash soft clay is remarkably higher than normal muddy clay. However,more than 85% of its soil particles is silt soil particle and the shear strength increases significantly after vacuum consolidation improvement.The authors believe the most reasonable explanation is:during the volcano explosion,the eruption gets cooling down in a very shot time and forms a lot of silt particle with void inside the particle.Those inner-particle void can contain a lot of water which results that the water content of volcanic ash soft clay is significantly higher than normal muddy clay.But those inner-particle water doesn't influence the stress behavior between soil particles. Therefore,the shear strength increment of volcanic soft clay in consolidation process is still matched with the prediction.