This study focuses on the Yanmazhuang West Station and Jinan West Railway Station of Jinan Rail Transit Line 1, China, examining the dynamic characteristics of eight-layered silty clay and subway station responses in Jinan. Through shaking table model tests, including free-field, two-story two-span, and three-story three-span stations, it finds relationships between the silty clay's dynamic shear modulus ratio and strain, damping ratio and strain, and confining pressure and dynamic shear modulus. It also reveals soil and station structural seismic responses to different intensities and waves.

In order to explore the influence of wheel surface structure on the trafficability of planetary rovers on soft ground, three kinds of wheels with different rigid wheel surface structures were selected for research. The basic performance parameters of the wheel on simulated planetary soil are measured and tested to explore the law of the wheel's sinkage, slip rate and traction coefficient. The results show that the wheel grouser increases the sinkage and slip rate of the wheel. The tread reduces the sinkage of the wheel, but it also reduces the traction performance of the wheel at a higher slip rate. Considering the complex working conditions of the planetary rover on the soft ground, the six-wheeled three-rocker-arm planetary rover is used to carry out passability tests in three terrains: obstacle crossing, out of sinkage and climbing. The results show that the grousers can cause disturbance and damage to the soft soil and have significant passing advantages. There may also be a slip phenomenon when crossing the obstacle, but it does not affect passing. The completely closed tread structure will cause soil accumulation between the tread and the grouser, affecting the wheel's ability to escape sinkage. This study provides a reference for the design of a rigid wheel surface structure for planetary rovers from the perspective of passing performance.

The deformation characteristics of river embankments on soft ground, improved by circular deep mixed columns and a combination of circular and grid-form columns, were investigated via two centrifugal model tests. The results indicate that the slope stability of the river embankment was effectively sustained in both cases. The combined reinforcement method exhibited superior overall performance, significantly reducing settlement. The greatest settlement was observed at the top of the river embankment, and although the settlement had not fully stabilized one year after construction, the settlement rate had slowed. Compared with the circular reinforcement alone, the river embankment maximum settlement was reduced by 25.3% in the combined reinforcement. Additionally, the grid-form columns effectively reduced the horizontal displacements in the middle and lower parts of the foundation. The deep-mixed columns performed effectively in providing support and reinforcement, and none of the piles reached the bending capacity during the test process. Given the stiffness difference between the columns and the surrounding soil, the stress distribution exhibited a stress concentration effect in the model. The measured column soil stress ratio ranged between 2 and 3, which is considered reasonable. The pronounced stress concentration effect of the mixing columns contributed to a faster consolidation rate of the foundation. On the basis of the measured settlement and excess pore water pressure, the degree of consolidation of the circular column-reinforced foundation one year after construction reached over 90% and 80%, respectively. For the foundations reinforced with combined circular and grid-form deep mixed columns, the degree of consolidation reached over 80% and 75%, respectively.

Vacuum preloading and composite ground reinforcement are commonly used methods for reinforcing soft soil, but there is a lack of integrated design method for vacuum preloading combined with composite ground. This case study introduces an innovative approach that combines vacuum preloading with liquid bag pressurization to achieve the integrated design of consolidation drainage method and composite ground reinforcement, which is different from the reported air bag pressurization. To illustrate the effectiveness of this method. Model tests were carried out to analyze the variation of water discharge, pore water pressure, ground settlement, and average consolidation degree in the process of vacuum consolidation. The study investigated the water content, undrained shear strength, and ground bearing capacity of composite ground after ground treatment. A correlation between average undrained shear strength and characteristic value of ground-bearing capacity was established to evaluate and predict the treatment effect of composite ground. Research shows that compared with traditional vacuum preloading, the undrained shear strength can be increased by 13.78%-65.08%, and the characteristic value of bearing capacity for the composite ground can be enlarged by 2.3-4 times. These results indicate that the vacuum preloading combined with liquid bag pressurization can significantly improve reinforcement effect on soft ground.

High-speed train (HST) running in the saturated soft ground induces significant vibration that may threaten the running safety and serviceability of high-speed railway (HSR). Extensive studies have been conducted on the dynamic responses of HSR, yet, the soil-water coupling and plastic behavior in the saturated soft ground are rarely considered, and thus the build-up of excess pore water pressure (EPWP) and displacement cannot be accurately calculated. In this study, 2D soil-water coupling elastoplastic FEM was employed to investigate HST induced vibration in the pile-supported embankment using FE code called DBLEAVES. Dynamic soil stress, EPWP, acceleration and displacement under different cases were numerically analyzed in detail. Numerical tests confirm that liquid phase in soft ground plays important influence on the dynamic responses that vertical acceleration and displacement will be overestimated while the horizontal acceleration and displacement as well as EPWP will be underestimated if soil-water coupling is not considered. Single-phase analysis also exaggerates the acceleration attenuation and underestimate the vibration amplification in soft ground. The existence of piles can induce significant soil arching effect in the embankment, the distributions of vertical acceleration and EPWP are partitioned sharply by the piles while vertical displacement in soft ground becomes more uniform along the depth direction within the pile reinforced area. The existence of piles also induces stronger vibration beneath the pile end so that larger EPWP is generated below the pile end than around the pile body. The main influence area due to HST vibration for pile-supported embankment is overall 20 m away from the centerline of HSR track, therefore, it is reasonable to improve the ground by properly increasing the number of pile within this area. When the number of pile is determined, increasing the length of pile or reducing the pile spacing are two effective ways to mitigate the dynamic response.