Qian-Qing Zhang

In this study, to solidify the silt in an expressway, a stabilizing agent composed of industrial wastes, such as ordinary Portland cement (OPC), calcium based alkaline activator (CAA), silicate solid waste material (SISWM) and sulfate solid waste material (SUSWM) was developed. Orthogonal experiments and comparative experiments were carried out to analyze the strength and water stability of the stabilized silt, and get the optimal proportion of each component in the stabilizing agent. A series of laboratory tests, including unconfined compressive strength (UCS), water stability (WS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses, were conducted on solidified silt samples treated with the stabilizing agent at optimal mixing ratios of OPC, CAA, SISWM, and SUSWM to elucidate the evolution of mineral composition and microstructure.

To reveal the deformation characteristics of soil in the shield tunnels section during proximity pile foundation excavation and to establish the convergence model for the tunnel excavation section. A model test of shield tunnel excavation adjacent to piles was carried out in this paper. Based on the data collected using a developed monitoring device for soil displacement in the tunnel section，the soil deformation law of excavation section under various conditions was analyzed. Additionally，a loss contour for the tunnel section exhibiting a non-uniform convergence mode was proposed. A mapping function expression for the Laurent series of the tunnel excavation loss section was established based on the theory of complex functions. The results indicated that the deformation of the tunnel arch bottom lagged behind that of the tunnel vault，and the deformation of the soil around the tunnel section was restrained by the adjacent piles. Comparisons between the calculated and measured values were made to evaluate the validity of the mapping function expression for the tunnel excavation loss section.

This paper presents a analytical approach for the analysis of the response of a single pile and pile group subjected to tension load by the load-transfer approach. The shaft displacement of a tension pile is assumed to comprise the relative displacement of disturbed soil around a pile and the elastic vertical soil displacement. Considering the interactive effects among piles, a new load transfer function of the individual pile in a pile group is proposed. In addition, an effective calculate method is developed for analyzing the response of a single pile and a pile group subjected to tension load. Comparative analyses are then performed to demonstrate the veracity of the proposed method. The comparative analysis results show that the proposed approach is reliable for the analysis of the response of single piles as well as pile groups subjected to tension load.

This note presents an analytical method for predicting the uplift capacity of a single pile embedded in sand, considering the arching effect. Taking into account the passive stress state of dense sand and the active stress state of loose sand adjacent to uplift pile, a theoretical solution for the lateral earth pressure coefficient for sand with different soil densities is proposed. The failure surface was assumed to be an inverted frustum of a cone with a characteristic angle of inclination. Using the limit equilibrium method, a closed-form solution for the uplift capacity of a single pile embedded in sand was established without requirement of any charts or tables. To assess the roles of the arching effect on the accurate prediction of uplift capacity and the reliability of the proposed analysis approach, comparisons between theoretical and available laboratory experiments and field test results, on sand ranging from loose to dense, were made.