Abstract:Particle size is one of the important factors that affect loess seismic subsidence. In this study, samples were collected from the muddy debris of Aiqi Gully mud volcano and nine samples were obtained from the sedimentary sections in surrounding mud volcano area. Laser test was used to determine particle size. Particle size parameters such as median value (Md), mean value (Mz), standard deviation (σφ), skewness (SK1), and kurtosis (KG) were analyzed. Results show that the Aiqi Gully volcano samples are dominated by silt (56%) and clay (44%). The particle size distribution is characterized by partial modality and positive skewness. The particle size of the sedimentary stratum samples are dominated by silt, which accounts for 60%-70%, and the clay contents considerably vary in different strata. Some sediment samples contain 15%-20% clay and 10% very fine grains. The grain size characteristics are similar to those of Tianshan loess. The clay content in the loess directly affects its seismic resistance, that is, the anti-seismic resistance of the loess increases with increasing clay content. The sedimentary grain size significantly increases in the clay component after transformation by mud volcanic sedimentation. Therefore, the sediments are gradually transformed from silty loess to clay loess by mud volcanic activity. The stability of the clay loess is high, thereby improving the seismic resistance of the sediments. However, the seismic resistance of the loess is affected by many factors. As such, further study is needed to quantitatively analyze the influence of mud volcano activity on the site seismic subsidence disaster.
