Understanding pit slope movements

Slow to extremely slow landslides in urban areas may cause severe damage to buildings and infrastructure that can lead to the evacuation of local populations in case of slope accelerations. Monitoring the spatial and temporal evolution of this type of natural hazard represents a major concern for the public authorities in charge of risk management. Pariana, a village with 400 residents located in the Apuan Alps (Massa, Tuscany, Italy), is an example of urban settlement where the population has long been forced to live with considerable slope instability. In the last 30 years, due to the slope movements associated with a slow-moving landslide that has affected a significant portion of the built-up area, several buildings have been damaged, including a school and the provincial road crossing the unstable area, leading to the need for an installation of a slope monitoring system with early warning capabilities, in parallel with the implementation of mitigation works. In this paper, we show how satellite multi-temporal interferometric synthetic aperture radar (MT-InSAR) data can be effectively used when coupled with a wireless sensor network made of several bar extensometers and a borehole inclinometer. In fact, thanks to their wide area coverage and opportunistic nature, satellite InSAR data allow one to clearly identify the spatial distribution of surface movements and their long-term temporal evolution. On the other hand, geotechnical sensors installed on specific elements at risk (e.g., private buildings, retaining walls, etc.), and collected through Wi-Fi dataloggers, provide near real-time data that can be used to identify sudden accelerations in slope movements, subsequently triggering alarms. The integration of those two-monitoring systems has been tested and assessed in Pariana. Results show how a hybrid slope monitoring program based on the two different technologies can be used to effectively monitor slow-moving landslides and to identify sudden accelerations and activate a response plan.

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Comprehensive Overview of Historical and Actual Slope Movements in the Medieval Inhabited Citadel of Sighisoara

Advancing Culture of Living with Landslides ◽

10.1007/978-3-319-53483-1_17 ◽

2017 ◽

pp. 147-157

Author(s):

Andreea Andra-Topârceanu ◽

Mihai Mafteiu ◽

Mircea Andra-Topârceanu ◽

Mihaela Verga

Keyword(s):

Comprehensive Overview ◽

Slope Movements

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Landform analysis of slope movements using DEM in Higashikubiki area, Japan

Computers & Geosciences ◽

10.1016/s0098-3004(00)00144-8 ◽

2001 ◽

Vol 27 (7) ◽

pp. 851-865 ◽

Cited By ~ 29

Author(s):

Junko Iwahashi ◽

Shiaki Watanabe ◽

Takahiko Furuya

Keyword(s):

Slope Movements

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An Emerging Methodology of Slope Hazard Assessment for Natural Gas Pipelines

Volume 1: Codes, Standards and Regulations; Design and Constructions; Environmental; GIS/Database Development; Innovative Projects and Emerging Issues ◽

10.1115/ipc2000-159 ◽

2000 ◽

Author(s):

Z. Joe Zhou ◽

Bill Liu ◽

Gregg O’Neil ◽

Moness Rizkalla

Keyword(s):

Natural Gas ◽

Public Information ◽

Ground Movement ◽

Management Approach ◽

Hazard Management ◽

Slope Movements ◽

Natural Gas Pipelines ◽

Site Investigations ◽

The Impact ◽

Ranked List

TransCanada Pipelines Ltd. (TransCanada) operates approximately 37,000 km of natural gas gathering and transmission pipelines. Within the Alberta portion of this system there are almost 1100 locations where the pipeline(s) traverse slopes, primarily as the line approaches and exits stream crossings. In the past, the approach to managing the impact of slope movements on pipeline integrity has been reactive; site investigations and/or monitoring programs would only be initiated once the slope movements were sufficiently large so as to easily observe cracking or scarp development. In some cases these movements could lead to a pipeline rupture. To move to a proactive hazard management approach and to optimize the maintenance expenditure, TransCanada has developed a new slope assessment methodology. The objective of this methodology is to establish a risk-ranked list of slopes upon which maintenance decisions can be based. Using only internal and public information on site conditions as input to predictive models for rainfall-ground movement and pipe-soil interaction, a probability of pipeline failure can be generated for each slope. Estimates of risk using a consequence-matrix approach enabled the compilation of a risk-ranked list of hazardous slopes. This paper describes this methodology, and its implementation at TransCanada, and presents some of the results.

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The 1998 Tatopani Landslide in the Kali Gandaki Valley of Western Nepal: cause and relation to mass rock creep

Journal of Nepal Geological Society ◽

10.3126/jngs.v22i0.32376 ◽

2000 ◽

Vol 22 ◽

Author(s):

Hellmut R. Volk

Keyword(s):

Slope Instability ◽

Low Grade ◽

Left Bank ◽

Main Central Thrust ◽

Slope Movements ◽

Wedge Failure ◽

Rock Avalanches ◽

Rock Creep ◽

Mass Rock ◽

The Village

The village of Tatopani lies on a small gravel terrace in the middle reach of the Kali Gandaki River, along a narrow course of about 2 km in length. One kilometre south of the village, a major rockfall occurred recently in the region of the Lesser Himalaya, which is built up of low-grade metamorphic rocks of the Kuncha Group, consisting of a thick sequence of foliated phyllites and bedded quartzites as well as interlayering of both lithologies. The monoclinal structure of these metasedimentary rocks is clearly related to the general trend of the Nepal Himalaya near the Main Central Thrust (MCT): strike NW-SE 140- 150°, dip 25-45° NE. Besides a clear foliation in the phyllites (s1) parallel to the quartzite bedding (s0), four other discontinuities are also developed as steep joints (j1-j4). Two joint sets j1 and j2, both crossing each other and both acting in conjunction with the foliation (s1) as a shear plane, were responsible for the wedge failure of the Tatopani Landslide, which led to a rockfall and avalanche of about 400,000 cubic metres and dammed the river for about 72 hours. It is noteworthy that several other - strikingly similar but older - weathered wedge failure surfaces are exposed at various spots all over the same ridge, which is the spur-ridge dividing the Kali Gandaki River from the Gar Khela tributary. This visible slope instability evidenced by relatively small wedge failures is causally connected with a much larger mechanism, namely mass rock creep or "sagging"- a purely gravitational slope deformation. The repeatedly occurring wedge failures producing landslides (rockfalls and rock avalanches) are caused by extreme shear stress and deep-reaching joints and fissures during mass rock creep. Only the final trigger for landslides or rockfalls is provided by extreme and lengthy monsoon rainstorms, which reinforce the cleft-water pressure inside rock discontinuities and openings, especially along the impermeable interface of quartzites and phyllites (s0 =s1) at the base of the wedge failure. The right (western) bank above the village is morpho-dynamically active also through mass rock creep and “pushes” laterally against the river course. However, the kinematics of the rock slope is rather different because the foliation geometry is more important. The foliation dips obliquely towards the riverside and consequently has facilitated extremely slow large scale dip slope movements along quartzite-phyllite interfaces (s0) without any catastrophic danger. However, the creeping slope movements of thick quartzite: members caused a set of conjugate extension faults producing toppling at the distal slope margins. Rock avalanches from the spur-ridge on the eastern (left) bank of the Kali Gandaki River S of Tatopani will always remain a threat, especially when excessive seasonal rains increase the cleftwater pressure inside the invisibly slow creeping system of the steep bank in an extraordinary manner.

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