hydro-mechanical process of LUSI mud volcano

通过室内试验，对发生泥浆喷发灾害的东爪哇地区沉积岩的水力特性进行了测定。根据室内试验结果，利用数值模型对孔压的时空分布进行了评价。数值模拟结果表明，在富含粘土的地层中会产生异常高的孔压，这主要是由于地层渗透率极低，沉积速度较快所致。流变学测试表明，泥浆粘度随液体含量和应变的增加而降低。研究结果表明，富含粘土地层的超压形成和流体注入均导致沉积物减少，是陆寺泥浆喷发的原因之一。

Hydraulic properties of sedimentary rocks in East Java where the disaster of mud eruption (LUSI) was occurred were measured by laboratory tests. Temporal and Spatial pore pressure distribution was evaluated by numerical model based on laboratory results. The numerical results showed that abnormally high pore pressure would have been generated at a clay rich formation that is the origin of erupted mud, and it is mainly caused by the formation of very low permeable layer and rapid sedimentation rate. Rheology measurement showed that viscosity of mud was decreased with increasing of liquid fraction and strain. Our result indicates that overpressure generation and fluid injection to the clay rich formation, both of which induce the reduction of sediment, is one of reasons for LUSI mud eruption.