A load transfer approach to rectangular closed diaphragm walls

Abstract

As a new type of bridge foundation, rectangular closed diaphragm walls (RCDWs) provide an efficient solution to controlling the settlement of high-speed railway bridges. However, the scant research on settlement prediction for RCDWs has hindered their application in practical engineering. This paper attempts to establish a simplified approach for predicting the settlement of RCDWs. First, a simplified analytical model of an RCDW is established in accordance with the load transfer approach. Then, the load transfer curves and related coefficients of skin friction and foot resistance are discussed, and special attention is given to the determination of inner skin friction based on the results of a model test. In addition, an iterative procedure is applied to facilitate the solution process; moreover, a program named SPFRCDW, written in Matlab, is developed to estimate the settlement of RCDWs based on the proposed approach. Finally, a case study is conducted to verify the calculation results of SPFRCDW. The results predicted by the proposed method are shown to agree well with the measured data.

Uplift behavior of nodular diaphragm wall: Experiment and theory

“…The similar material of the diaphragm wall is made of plexiglass (PMMA) with a Young's modulus of 2.542 GPa obtained by hydraulic press test, and the surface of the wall is adhered with sand to simulate the actual roughness of the concreting wall, 18,19 as shown in Figure 3A. It should be noted that the blue part in Figure 3 is the protection tape that will be removed during the installation process.…”

“…This choice closely simulates the actual working conditions observed at the interface between concrete and soil, aligning with previous studies indicating that the interfacial friction angle between concrete and soil typically ranges from 0.75 to 0.95 times the soil's internal friction angle. [18][19][20]…”

“…The hyperbolic model is widely used to define the transfer function of skin friction between foundation and soil. 18,19,32 In this paper, the hyperbolic model is adopted as the transfer function of skin friction τ s , and can be defined as…”

“…Since P bi = P td and S bi = S td , the skin friction τ si can be calculated by Equation (8). Meanwhile, the force P ti acting on the top of unit i and the displacement S ti can be obtained through Equations ( 17) and (18). At this point, the tensile deformation in the middle of unit i can be given as…”

Editorial

“…The third paper by Wu et al (2016) is also concerned with the foundations of a bridge for a high-speed railway. In this paper, the authors present a novel foundation system consisting of rectangular closed diaphragm walls, which provides an efficient system for controlling the bridge settlement.…”