A device for rainfall simulation in geotechnical centrifuges

Abstract

Rainfall-induced slope instabilities are ubiquitous in nature, but simulation of this type of hazards with centrifuge modelling still poses difficulties. In this paper, we introduce a rainfall device for initiating slope failure in a medium-sized centrifuge. This rainfall system is simple, robust and affordable. An array of perforated hoses is placed close above the model slope surface to generate the raindrops. The rainfall intensity depends on the centrifuge acceleration and the flow rate of the water supply, which is controlled by the size and number of the tiny pinholes in the hose walls. The rainfall intensities that are tested range from 2.5–30 mm/h, covering the intensity range of moderate, heavy and torrential rainfall events. Our model test with rainfall-induced slope failure shows that this system is capable of generating relatively uniform rainfall of wide intensities and leads to various patterns of slope failure.

A Systematic Review of Physical Modelling Techniques, Developments and Applications in Slope Stability Analyses

“…Severalscholars, including Wang et al [4], Greco et al [110] and Ng et al [111], have utilised geotechnical centrifuge equipment as a physical modelling tool to investigate various slope stability problems. The theory and working principle of geotechnical centrifuge have been extensively discussed elsewhere [115,116].…”

“…Uniform rainfall is difficult to generate when nozzles are used because they cover a circular area. Thus, in the enhanced acceleration field, nozzles often produce a core zone with a higher rainfall intensity than the outside areas [4]. Similarly, the application of atmospheric chambers, as highlighted by Ng et al [114], does not fully replicate rainfall conditions because the approach is based on increasing the humidity to induce porewater pressure increments within the soil voids.…”

“…Similarly, the application of atmospheric chambers, as highlighted by Ng et al [114], does not fully replicate rainfall conditions because the approach is based on increasing the humidity to induce porewater pressure increments within the soil voids. However, Wang et al [4] proposed a simple rainfall device for application of physical modelling tests in a geotechnical centrifuge environment. The device, free of pressurised water connections and generating mist nozzles, was able to provide uniform rainfall with a wide spectrum of rainfall intensities (2.5 -30 mm/hr).…”

“…Using physical models in slope stability has attracted increased interest in enhancing current theory and understanding. The approach requires that a critical or influencing factor(s) is being studied; these factors could be rainfall or water infiltration [4], dynamic loading such as earthquake [5,6], joint action of rainfall and landslides [7], and static loading [8], coupled effects of rainfall and dynamic loads [9,10], orientation of rock slope discontinuities [11], slope reinforcements [12,13], rock block proportions and orientations in soil-rock slopes [14], failure mechanisms of soil and rock slopes [15], overburden loading [16], surcharge loading [17], slope stabilisation [18], rock joint surface shapes [19] and many more. This attests to the versatility and relevance of the physical modelling technique in slope stability research.…”

An experimental study on aerodynamic characteristics of hypergravity centrifugal facility

“…Centrifugal modelling is widely recognized as a valuable approach in various fields, including slope and high dam engineering, geotechnical earthquake engineering, deep-sea engineering, and advanced material preparation research (Lu et al 2011;Liu et al 2018;Chortis et al 2020;Weng et al 2020;Wang and Idinger 2021). In 1931, the earliest centrifugal test was conducted at Columbia university to investigate the integrity of mine roof structures in rock (Bucky 1931).…”