Stability monitoring of a rail slope using acoustic emission

Abstract

The paper details the use of acoustic emission generated by active waveguide subsurface instrumentation to monitor the stability of a rail soil cutting slope failure. Operation of the active waveguide, unitary battery-operated acoustic emission sensor and warning communication system are described. Previous field trials reported by the authors demonstrate that acoustic emission rates generated by active waveguides are proportional to the velocity of slope movement, and can therefore be used to detect changes in rates of movement in response to destabilising and stabilising effects, such as rainfall and remediation, respectively. The paper presents a field trial of the acoustic emission monitoring system at a reactivated rail-cutting slope failure at Players Crescent, Totton, Southampton, UK.The results of the monitoring are compared with both periodic and continuous deformation measurements. The study demonstrated that acoustic emission monitoring can provide continuous information on displacement rates, with high temporal resolution. The ability of the monitoring system to detect slope movements and disseminate warnings by way of text messages is presented. The monitoring approach is shown to provide real-time information that could be used by operators to make decisions on traffic safety.

An acoustic emission landslide early warning system for communities in low-income and middle-income countries

“…Extensive research including multiple field trials (e.g. Berg et al 2018;Dixon et al 2015a;Dixon et al 2015b;Smith and Dixon 2015;Smith et al 2014;Smith et al 2017a) has demonstrated that AE rates are indicative of slope displacement rates, and hence, this instrumentation is defined as a slope displacement rate sensor. Activity status of the slope (e.g.…”

“…AE monitoring is not as well developed in geotechnical monitoring applications as in other industries due to low energy levels of generated AE and the high attenuation of signals as they propagate through the ground, both of which make it challenging to detect and quantify AE. However, recent research and advances in instrumentation have resulted in successful applications using AE to monitor soil slope stability (Berg et al 2018;Dixon et al 2015aDixon et al , 2015bSmith and Dixon 2015;Smith et al 2014Smith et al , 2017a. This body of work has proven that monitoring AE can be used to provide an early warning of slope instability by detecting both the development of shear surfaces and accelerating deformation behaviour (Chichibu et al 1989;Fujiwara et al 1999;Koerner et al 1981;Michlmayr et al 2017;Nakajima et al 1991;Smith et al 2017a).…”

Current and future role of instrumentation and monitoring in the performance of transport infrastructure slopes

“…Sold as a commercial system and has been used fairly widely in stable and unstable infrastructure slopes (e.g. Dixon et al 2015). Most likely to be used for applications (1), (2), (3) and (5) in Table 2 Active and at the BIONICS facility (Glendinning et al 2014), with a number of other installations in natural landslides.…”

Photographic feature: Acoustic emission monitoring of coastal slopes in NE England, UK

“…The AE monitoring approach employs an active waveguide (Figure 1), which is a subsurface instrument installed inside a borehole that intersects existing or potential shear surfaces beneath the slope (Smith et al, 2014a;Dixon et al, 2015a;Dixon et al, 2015b;Smith & Dixon, 2015;Smith et al, 2016a;Smith et al, 2016b;Smethurst et al, 2017). It can also be retrofitted inside existing inclinometer (e.g.…”

“…In this study, voltage threshold levels of 0.25V and measurement intervals of 30-minutes were used. Figure 3a shows continuous cumulative RDC and deformation time series measurements from an active waveguide and ShapeAccelArray (SAA) in-place inclinometer installed through a reactivated natural soil slope (after Smith et al, 2014a;Dixon et al, 2015b) Borough Council to commission ground investigations, which have been interpreted by Halcrow (now CH2M) to facilitate stability assessments and inform on-going risk assessments and site management.…”