Stability Control of Staged Filling Construction on Soft Subsoil Using Hyperbolic Settlement Prediction Method: A Case Study of a Tidal Flat in China

An improved method, which combines in situ measured settlement data, hyperbolic method, and deep lateral displacement rate, is presented in this study to predict the consolidation and stability of the ground, which can be used in conducting staged filling construction on soft subsoil. A case history of a highway embankment construction in a tidal flat with thick mucky clay is studied in Xia Pu, China. Preloading with the prefabricated vertical drain method is adopted to accelerate the consolidation of a subgrade. The field behavior of soft ground under filling load is observed through in situ monitoring sensors in four typical sections. The final ground settlement in each stage is determined using the field monitoring data based on the hyperbolic settlement prediction method. For each stage of graded filling load, the ground settlement with a strain consolidation degree of 95% is defined as the standard settlement, and the corresponding settlement time is set as the standard settlement time. The preloading period is estimated according to the standard settlement time. The deep lateral displacement rate of the ground is monitored to control the stability of the foundation and recommended to guide the embankment construction. Results indicate that the presented method can predict the preloading time of graded filling, reduce the frequency of observation, and ensure the consolidation and stability of the ground.

Working Performance Analysis of Reinforced Gravel Cushion on Soft Subsoil

Model tests are performed to study the working properties of reinforced and non-reinforced gravel cushion on soft subsoil. The effects are analyzed of reinforced materials on the bearing characteristic of the cushion. The stress field and settlement field are studied through the method of numerical simulation. The results show that: The bearing capacity of foundation with cushion increases significantly when the cushion is reinforced. Under the same condition, the effect of geocell reinforcement is better than geogrid reinforcement. The value of coefficient of subgrade reaction increases when the cushion is reinforced. The reinforced materials can adjust the stress distribution and settlement distribution of the cushion.