Experimental study on mitigation of liquefaction-induced vertical ground displacement by using gravel and geosynthetics

Abstract

Background: Earthquakes in liquefaction-prone areas are frequently followed by the settlement of surface structures due to subsoil liquefaction. This paper aims to study the influence of geosynthetics along with gravel usage to reduce the vertical soil displacement caused by liquefaction using a shake table equipment. This influence is analyzed by means of measuring soil acceleration, pore water pressures and vertical soil deformation due to the shaking process. Results: Results of a series of 1-g shaking table tests which have been conducted in different initial relative densities which are 50% (loose sand conditions) and 90% (dense sand conditions) to evaluate the performance of proposed mitigation against settlement problem are presented. It is found that ground settlement reduced around 11.4 mm for loose sand conditions, from 20.9 mm in the case with no countermeasure (Case 1) to 9.5 mm in the Case reinforced with gravel and geosynthetics Type II (Case 4). Correspondingly, for dense sand states, the settlement decreased by about 1.8 mm, from 5.6 mm in the Case 1 to 3.8 mm in Case 4. Moreover, a differential settlement between loose sand and dense sand conditions decreased as well, around 9.6 mm, from 15.3 mm in the Case 1 to 5.7 mm in Case 4. Conclusions: By conducted a series of shake table tests, it is confirmed that the vertical ground displacement decreased by the use of geosynthetics and gravel up to 54% and 32% for loose sand and dense sand states, respectively. Furthermore, test results also show that there is a decrease in the differential settlement between loose sand and dense sand conditions, around 62%.

Study comparison of ground subsidence due to preloading installation of egg tray triangular vertical drains with distance variations on a small laboratory scale

“…Strengthening work on consolidation problems can be carried out in various ways, namely: first, remove the poor native soil and replace it with another [6][7][8], more stable type of soil. Second, carrying out stabilization, such as using geosynthetic materials for vertical channels and speeding up the process of draining pore water or removing water from the soil pores first using a preloading system [9], then, after the soil is stable, building buildings on it. Study of consolidation problems by utilizing egg tray waste as vertical drain material to speed up the consolidation process, accompanied by the use of a preloading system [10].…”