In this study, a novel analytical approach is proposed to calculate the passive earth pressure against a rigid retaining wall subjected to the translation mode. Effects of arching in cohesive backfill soils as well as friction mobilized along the wall–soil interface are considered. Analytical expressions of the earth pressure, passive resistance, and its height of application on the backface of the retaining wall were derived based on static equilibrium of forces under passive conditions acting on the failure wedge. A parametric study was undertaken to assess effects of internal friction angle of backfill, wall–soil interface friction angle, surcharge pressure, cohesion, unit weight, and inclination angle of the slip surface on the active earth pressure as well as on the slip-surface angle. The results of the proposed method were then verified against the existing test data as well as the predictions by Coulomb theory and Rankine theory. The results show that the proposed method yields satisfactor...
1 July 2018 in International Journal of Geomechanics
Considering the effects of the rotation of the principal stresses, time effects, and wall–back inclination, a new solution for the seismic active failure angle is derived by the pseudodynamic method, according to the total force equilibrium of the sliding soil mass. Through a horizontal differential layer method, new differential equations of the normal seismic active earth pressure and its coefficient for an inclined rigid retaining wall are obtained under translation. Then, using numerical solutions for ordinary differential equations based on the Runge–Kutta method, influences of parameters (i.e., the vibration period time, wall–back inclination, internal friction angle of backfill, wall-soil friction angle, height of wall, amplitude of horizontal, and vertical seismic acceleration coefficient) on the seismic active failure angle are discussed, as well as the seismic active earth pressure and its coefficient. Moreover, the seismic active earth pressures and its coefficients calculated by proposed method are compared with those by existing pseudostatic and pseudodynamic methods. The results showed that the seismic active failure angle, seismic active earth pressure and its coefficient all change periodically with the time, and the distribution of seismic active earth pressure is nonlinear along the wall height. The seismic active earth pressure and its coefficient found in this paper are larger than those found using existing pseudostatic methods.
1 December 2018 in KSCE Journal of Civil Engineering
This paper reports a new method for calculating the active earth pressure acting on inclined rigid retaining wall with inclined backfill, considering wall-soil interface friction angle. Based on Mohr-Coulomb strength theory and Mohr stress circle, new formulae of the active earth pressure and the active rupture angle are derived. The effects of internal friction angle, backfill-surface inclination, wall-back inclination on the active earth pressure and the active rupture angle are investigated. In order to facilitate calculation, special solutions of presented formulae are discussed under various particular conditions. Finally, the calculated results from the presented formula and existing formulae are compared with existing small-scale test results. The comparison shows that the presented method satisfactorily predicts active earth pressure.
Pullout tests on geogrids have been regarded as the most direct way to investigate geogrid–soil interaction. In the pullout tests on geogrids, either static or dynamic load is commonly used for applying the vertical loads. In order to investigate the influence of static and dynamic load on pullout test results, pullout tests are carried out to analyze the mechanical response of geogrids and soils under static and dynamic load from the large-scale pullout tester. The results show that frequency and amplitude have significant effects on the pullout test results under the dynamic load. The interface cohesion and friction coefficients under dynamic loads are smaller than those under static loads. The reinforcement effect of geogrids is reduced by dynamic load. Therefore, the strength of geogrids should be reduced when quasi-static analysis is used for reinforced structures. Knockdown factor is recommended for the corresponding reduction. The investigation results of this study may provide scientific references for regulating the design method of reinforced structures.
In order to investigate the mechanical behavior of reinforced soil-retaining walls during service, this paper carried out a long-term remote observation test for 6 years on the modular-reinforced soil-retaining wall of the Qingrong intercity railway in eastern China’s Shandong Province. During the construction period, earth pressure boxes, flexible displacement meters, settlement pipes and displacement meters were buried to observe the soil pressure, reinforcement strain, horizontal displacement and settlement of the reinforced earth-retaining wall, respectively, for a long time; then, the results were analyzed to summarize its variation law. The results show that the reinforced earth-retaining wall was stable after one year of construction. It was determined that the strain of reinforcement in each layer decreased with time, culminating in a value of less than 0.88 percent during the 6th year. The maximum horizontal displacement of the wall was 11.43 mm and the maximum settlement of the wall top was 46.77 mm, which were 0.15% and 0.60% of the wall height, respectively. These research results can be applied to the construction and design of reinforced soil-retaining walls in high-speed railways. The effects of the elastic modulus of filler, the tensile modulus of reinforcement and the reinforcement length on the characteristics of the retaining wall were analyzed in the numerical simulation with PLAXIS2D. The results and analysis show: the elastic modulus of filler and reinforcement length have a significant effect on the horizontal displacement of the retaining wall. The results of this experiment can be referenced for engineering projects.