Continuous Slope Mass Rating Research Articles

Assessment of Rock Slope Stability Along Degala-Koya Road, Erbil, NE Iraq

This article addresses the issue of instability in rock slopes along the main Degala-Koya road in Erbil northeastern Iraq, which poses a significant threat to human safety and property. the use of Slope Mass Rating Tool software and various techniques such as kinematic analysis and geomechanical classification to investigate cut slopes and assess slope stability. Geotechnical tests, including a point load test, were performed at eight stations in the study area to determine the unconfined compressive strength. comparison between discrete and continuous Slope Mass Rating values for rock slopes was carried out. The most unstable slope was identified as Station 4, while Stations 2, 5, 6, and 8 were deemed the most stable. The study found that rock fall accompanied by direct toppling was the most common type of failure, with plane sliding, rock fall, toppling, and wedge sliding as likely dominant failures. The Slope Mass Rating Tool-v205 software is more accurate When evaluating slope stability when strengthen with kinematic analysis by Dips-v6.008 software.

Evaluation of slope stability through rock mass classification and kinematic analysis of some major slopes along NH-1A from Ramban to Banihal, North Western Himalayas

The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes, which is vital for India's socio-economic growth. Due to natural and artificial factors, frequency of slope instabilities along the networks has been increasing over last few decades. Assessment of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the year. Several rock mass classification methods are generally used to assess the strength and deformability of rock mass. This study assesses slope stability along the NH-1A of Ramban district of North Western Himalayas. Various structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 slopes. For evaluating the stability of these slopes, kinematic analysis was performed along with geological strength index (GSI), rock mass rating (RMR), continuous slope mass rating (CoSMR), slope mass rating (SMR), and Q-slope in the present study. The SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely unstable. The stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating (SSR) for the factor of safety (FoS) of 1.2 and 1 respectively. Q-slope with probability of failure (PoF) 1% gives two slopes as stable slopes. Stable slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the FoS. The value ranges given by different empirical classifications were RMR (37–74), GSI (27.3–58.5), SMR (11–59), and CoSMR (3.39–74.56). Good relationship was found among RMR & SSR and RMR & GSI with correlation coefficient (R2) value of 0.815 and 0.6866, respectively. Lastly, a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.

Stability analysis of road cut slopes in Sikkim Himalaya along national highway 10, India

ABSTRACT The point-specific analysis of slope stability of road cut at nine locations was conducted along NH-10, between Rangpo and Ranipool in Sikkim, India. Kinematic analysis of discontinuities shows slope vulnerability to a union of failure types, namely, plane, wedge, and topple failure at different studied sites. Rock mass characterization was carried out on the basis volumetric joint count (Jv), RQD, RMR, and GSI. Appraisal of slope vulnerability to failure was done using traditional slope mass rating (SMR), Continuous SMR, Chinese SMR, and Q-slope stability method. Comparative analysis of different empirical methods proves a decent correspondence and shows that most of the cut slopes are under unstable to a partially stable condition. Stability method, Q-slope was used to analyse the stability conditions for 50%, 30%, 15%, and 1% probability of failure and to further find out stable slope angle for all the considered locations. The coalesced effort of the road cut stability analysis through kinematic and empirical methods will give insight into slope failure vulnerability along this highway by finding the most susceptible failure locations. The study will help to understand the dynamics of slope design for problematic stretches along NH −10 and adopt more effective remedial measures for better stability.

Graphical charts for onsite Continuous Slope Mass Rating (CoSMR) classification using strike parallelism and joint dip or plunge of intersection

We propose the new continuous slope mass rating (SMR) charts for easy calculation of SMR class of rock slopes in the field. SMR class can be determined by plotting the parallelism between dip directions of slope and discontinuity (slope dip direction and trend direction of intersection line in case of wedge failure) (A) in the x-axis and discontinuity dip amount (βj) (plunge amount in case of wedge failure (βi)) in the y-axis using SMR charts. We apply the proposed SMR charts to an assumed rock slope consisting of four joint sets and a basic Rock Mass Rating (RMRb) value of eighty. SMR class for the assumed rock slope was calculated using proposed SMR charts and by the existing Graphical Slope Mass Rating (GSMR) method. After comparing both the methods, we demonstrate, the proposed SMR charts prove to be simpler and take less time to evaluate SMR class as compared to the GSMR method. The GSMR method requires matching six stereonets for a single rock slope, whereas by using proposed SMR charts minimal use of stereonet is required to calculate trend and plunge of intersection. Proposed SMR charts incorporate the continuous functions (F1, F2, and F3) for SMR calculation, whereas a discrete rating system is used in the GSMR method. This study suggests, the proposed SMR charts are easy to use, more efficient, and can be adopted as a valuable tool for the preliminary rock slope stability assessment in mountainous areas like the Himalayas, where within a few meters joints and slopes geometries changes.

Integrated empirical and numerical approach for stability and failure analysis of cut slopes in seismically active Uttarakhand Himalayan, India

In the recent past, the upper range of the Himalayas witnessed numerous cases of disasters (such as Kedarnath tragedy) and was responsible for huge destructions and instability of many slopes along the National Highway (NH-7) Uttarakhand, India. The crucial part of the road passes through cut slopes comprised of highly jointed rock mass and strong variation in persistence, spacing, and degree of fracturing observed at different locations. As the area is located in the seismically active Lesser Himalayan region, where numerous slope failures of great magnitude may be anticipated. This study was carried out to predict the potential instability of eight different slopes along NH-7 from Kaudiyala to Karakot, Uttarakhand, using empirical and numerical methods. Preliminary stability assessment includes rock mass characterization, kinematic analysis, and continuous slope mass rating (CoSMR), where rocks are generally blocky (fair surface) and undergoes mostly wedge failure. CoSMR and Qslope, both indicate that three locations are partially stable, while the rest of the other locations are unstable. Results of newly developed [BQ] and [BQ]GSI systems are closely associated and classify slopes under partially stable (class III & IV) and unstable (class V), respectively. Afterward, an exhaustive study was carried out with numerical methods to inquire into failure mechanism and associated damage zone. The factor of safety was estimated from limit equilibrium, finite element stress-based approach, and continuum finite element method, where the majority of slopes are critically stable and unstable except few stable slopes. Further, the application of seismic loading substantially incited the slope instability, and result shows that the reduction in a static factor of safety is ranging from 22.22 to 50%, with an average of about 34.24% using different numerical methods. Additionally, seismic forces also alter the profile of stress–strain, strength, displacements, and other parameters predicted under the condition of gravity. Nonlinear Generalized Hoek-Brown failure criterion supersedes Mohr-Coulomb criterion failure almost in each profile and provides most vulnerability and authentic result in seismically active jointed rocks of Himalayan.

Study of qualitative stability analysis and rainfall thresholds for possible landslide occurrence: a case study of Sikkim Himalaya

Landslide hazard characterization in the Setijhora landslide, located near Kalijhora village, along National Highway 10, was carried out in a qualitative way using Rock Mass Rating (RMR), Continuous Slope Mass Rating (CSMR) and Geological Strength Index (GSI). CSMR data helped in the understanding of slope failures (wedge, planner, rotational and toppling), while RMR & GSI data provides a better understanding of rock mass quality and its deformation. RMR was observed between 10–49 in the dry season and 1–39 in the monsoon season. Kinematic/stereographic analyses indicate vulnerability to wedge failure, while CSMR ranges from 13.84 to 50.85 (class III to class V). Rainfall threshold data shows cumulative rainfall of more than 111.3 mm over 20 days and 222 mm in a month indicating a high probability of landslides occurrence. Data generated from the study will be very useful for developing landslide early warning in the study area.

Empirical and finite element based stability analysis of highway cut slopes in Uttarakhand Himalayan terrain, India

The present paper deals with different empirical methods and finite element method of slope stability analysis along National Highway (NH)-7, in Uttarakhand, India. The highway is only path in the hilly terrain of Lesser Himalayan for the public transport and have strategic importance due to militaries possession routes. This route is also significant due to having many holistic places, connecting to this. There was numerous landslides happened along the Highway in past due to various natural and anthropogenic activities. Hence, keeping an eye to the socio-economic development of the distant area, slope stability analysis is very crucial along the road cut sections. To identify the vulnerable locations and to collect the geotechnical data, the field investigation was carried out between Shivpuri to Byasi along NH-7 in Garhwal, Uttarakhand. Then geotechnical data was intended followed by rock mass characteristic, kinematic analysis and Qslope stability. Additionally, to review the stability results, numerical simulation (finite element method) was employed and slope mass behavior and failure mechanism of cut slopes were also evaluated. The rock mass characteristic and kinematic analysis illustrate normal and good variety of rock mass mainly wedge mode with flexural toppling of failure. The slope mass rating, continuous slope mass rating and also Qslope stability analysis showed, road cut slopes are critically stable and unstable. The results of different empirical methods shows a decent correlation between them. Further the numerical simulation analysis also evaluates that two cut slopes are unstable and other one is critically stable. This substantial empirical and numerical analysis of cut slopes provides a collective approach to stable and develop the holistic road corridor in Himalayan terrain.

Stability assessment of tunnel slopes along the Dujiangyan City to Siguniang Mountain Railway, China

This work focuses on integrated stability assessment of rocky tunnel slopes along a planned railway, namely, the Dujiangyan City to Siguniang Mountain Railway (DS Railway), which is an important transportation corridor in Southwest China. Investigating the stability of slopes at the entrances and exits of tunnels represents the first step of railway construction. Based on detailed geological engineering studies, the stability of 32 tunnel slopes was measured and evaluated by means of the slope mass rating (SMR), Chinese slope mass rating (CSMR) and Chinese continuous slope mass rating (CCSMR) systems. Moreover, a kinematic analysis technique was also employed to identify the potential failure modes of the jointed rock masses in tunnel slopes. The results reveal that the CSMR, by considering the slope height and discontinuity condition coefficient, can more robustly assess the slope stability than the SMR. Similarly, the CCSMR, which is based on continuous functions and can identify potentially dangerous slopes that should be reinforced, can reduce subjectivity. Many slopes deemed unstable and completely unstable by the CSMR and CCSMR are located on the banks of the river from Longchi to Longtan and from Xindianzi to Siguniang Mountain. The potential failure modes of the 32 slopes determined by kinematic analysis are basically consistent with the results obtained by the slope mass classification systems. These research results pave the way for stability assessment and intervention decision-making during the construction of the DS Railway.

Applicability of Q-slope Method in the Himalayan Road Cut Rock Slopes and Its Comparison with CSMR

The engineered slopes along transportation routes in the Himalayan region are manifested by multiple sets of discontinuities and are vulnerable to structurally controlled failures. The hazard potential along one such route was assessed by an empirical Q-slope method. The investigated engineered slopes along the route are unstable, and the Q-slope value ranges from 0.0023 to 0.7701. By considering the ongoing road development and excavation works, optimal angles without any requirements of reinforcement measures (β) were determined for the probability of failure (PoF) as 1%, 15%, 30%, and 50%. The outcomes obtained by Q-slope were also correlated with the continuous slope mass rating (CSMR) values. A linear relationship was obtained between Q-slope and CSMR values, having the coefficient of determination as 0.67. The study also aims to assess the applicability of the existing Q-slope method for toppling mode of failure. A modified Q-slope method for toppling failure is proposed by considering the basic principles of toppling failure. The role of joint roughness parameter in topple mechanism is highlighted. Consequently, chart based modifications along with proper guidelines for the newly introduced parameter has also been proposed. It is also pointed out that the Q-slope chart is slightly conservative in nature particularly for β corresponding to low Q-slope values. The optimal slope angle for the PoF 1% was correlated with the slope angle at factor of safety as 2, and an extended stable zone is proposed with further scope of development. The modifications and suggestions for the refinement of the system will enhance the applicability of the method for a much broader range of initial ground conditions. The outcomes may be advantageous for the progressing road widening and development work along a section of the transportation route in Uttarakhand Himalaya.

Analytical and Numerical Stability Analysis of Road Cut Slopes in Garhwal Himalaya, India

The rocks of the Himalayan terrain are highly deformed and distorted due to complex geological and tectonics setup. Failures of slopes are always reported along National Highway (NH)-7, in the Uttarakhand Himalayan region, which causes loss of lives, traffic blockage, and destruction of property and also deterioration of the environment gradually. The road cut slope stability analysis of five locations were carried out along NH-7, between Shivpuri to Kaudiyala in Uttarakhand, India. For that a rigorous field investigation was done to collect the geotechnical parameters of slopes and also the potential instability condition of cut slopes were monitored with real time. To know the characteristic of rock mass, the geotechnical data's were studied based on rock mass rating (RMR) and geological strength index (GSI). The kinematics of the blocky (good and fair) rock-mass shows in general wedge, toppling and planar type of failures for different rock slopes. The petrography of representative rock samples was also carried out to see the mineralogical variation in quartzite and phyllitic quartzite. The comparative analysis of different empirical methods for slope stability as slope mass rating (SMR), continuous slope mass rating (Co-SMR), and Chinese slope mass rating (CSMR) shows a decent correlation and revealed that slopes are mostly partially stable. Qslope stability has also been applied to reveal the stability problems and to find out stable slope angle for different slopes. Further to clarify the stability of these slopes, numerical models (LEM and FEM) were applied. The numerical result, (FoS) of different slopes revealed that slopes are stable, critically stable and unstable, with a good agreement between LEM and FEM models. The collective effort of slope stability analysis through analytical and numerical methods will give the better perception to find out the potential remedial measures and optimum slope design.

Geo-engineering classification with deterioration assessment of basalt hill cut slopes along NH 66, near Ratnagiri, Maharashtra, India

Western Ghats (WG) in India is endowed with one of the most distinctive and picturesque mountainous landscapes. The region encounters unprecedented rain and non-engineered excavations (especially along highway cut slopes), that turns out to be detrimental to the stability of rock and soil slopes. The present research focuses on accounting the vulnerability condition of rock slopes of differential deterioration intensities along National Highway corridor 66 (NH 66) at Ratnagiri–Sangameshwar (RS) stretch. Rock mass and associated slope stability condition were encapsulated, and studied locations were classified using different geo-engineering classification (GEC) systems such as RMR (Rock Mass Rating), SMR (Slope Mass Rating), CSMR (Continuous Slope Mass Rating), GSI (Geological Strength Index) and RDA (Rock slope Deterioration Assessment). The study introduces a new class in RDA for igneous rocks that are susceptible to high deterioration. Some useful insights have been added and discussed in the light of deterioration-induced block failures which have been integrated with detailed kinematic analysis. The present study recommends that RDA would prove more efficient and informative in the preliminary stage of slope stability investigation for high deterioration susceptible igneous rock masses as compared to other geo-engineering systems.

Rock slope stability along road cut of Kulikawn to Saikhamakawn of Aizawl, Mizoram, India

Landslide is a natural hazard which carries water, mud, debris and sometimes large boulders. Earthquakes, heavy rainfall and tectonic forces are natural responsible factors for landslides, whereas overpopulation and rapid development in the hilly region are unnatural factors which involve human activities such as construction/maintenance of roads, highways, railways and buildings by the unplanned excavation of rock slopes. Both natural and unnatural factors have been accountable for the increase in the probability of landslides in the past few decades. In the present study, stability analysis of rock slopes has been carried out along Kulikawn to Saikhamakawn road section of Aizawl. Kinematic analysis has been performed to identify the road cut slopes which have the potential to fail, and mainly two types of failures were found, i.e., wedge and topple failure. In order to check the stability of road cut slopes, Geological Strength Index, slope mass rating (SMR) and continuous slope mass rating (CoSMR) have been used in this study. Numerical modelling has also been performed to assess the stability of the road cut slope. The maximum displacement of 0.79 m with a maximum velocity of 0.78 m/s has been found for rock slope at location L1 using numerical modelling which confirms the finding from kinematic analysis, SMR and CoSMR analysis.

Landslide stability assessment along Panchkula–Morni road, Nahan salient, NW Himalaya, India

We report the slope stability analysis of three vulnerable sites (S1, S2 and S3) within the lower Siwalik along the Panchkula–Morni road section in the Nahan salient, north-western Himalaya. Kinematic analysis of joint data was conducted to understand the different modes of failure. Rock mass classification techniques like rock mass rating, slope mass rating (SMR) and continuous SMR were used for stability classification and the factor of safety was calculated using stability charts. At site S1, the instability is controlled by the orientation of the discontinuity joint J1 which is parallel to the bedding and at site S2, the slope fails due to the wedge. The Umri landslide site S3 is the product of a damage zone by the normal faults which intersect at joint J3; a wedge is formed which falls in the critical zone. The damage zone in the Umri landslide greatly affects the porosity and permeability of the rockmass and acts as a pathway for the percolation of water during rainfall which reduces effective stress. The slope failures are tectonically controlled results due to the high slope angles, structural discontinuities like joints and faults and structural damage zones associated with the faults.

Stability appraisal of road cut slopes along a strategic transportation route in the Himalayas, Uttarakhand, India

In precarious mountain terrains like the Himalayas, road cut slopes are highly vulnerable to slope failures. Slope failures in the region are often triggered by natural factors such as neotectonism, rainfall, seismicity, weathering, erosion, etc. However, rapid human intervention is an additional factor causing large-scale slope instability in the region. Unplanned excavations of slopes for construction and/or widening of roads decrease slope stability. The inevitable slope failures cause major inconvenience to tourists and residents and are also responsible for severe injuries and loss of lives and property. The present study incorporates a stability analysis of road cut slopes along National Highway 58 (NH-58) from Kaliyasaur to Rudraprayag, Uttarakhand. Vulnerable slopes were identified during the field survey. To evaluate stability conditions of rock mass, rock mass classification systems including rock mass rating (RMR), continuous slope mass rating and the Geological Strength Index (GSI) were employed to identify different stability grades. Furthermore, quantified GSI was correlated with basic RMR in a bivariate plot, which showed a linear relationship. Kinematic analysis was also carried out to identify the probability of structurally controlled failures due to adversely oriented discontinuities. Outcomes from different methods corroborated each other and matched the existing site conditions.

Comparative analysis of rockmass characterization techniques for the stability prediction of road cut slopes along NH-44A, Mizoram, India

The network of roads in hilly areas plays an important role in the socio-economic development of any country. Instability in road cut slopes is the most critical and common problem in the Northeast region of India. We conducted rockmass characterization of thirteen slopes from three regions, namely Lengpui, Phunchawng and Aizawl Zoo areas near the Aizawl city, on the basis of rock mass rating (RMR), geological strength index (GSI), kinematic analysis, and various slope mass rating techniques. Wedge failure was observed to be prominent in these regions, though some other modes of failure were present at the site. The stability of road cut slopes was found to vary from partially stable to completely unstable with regard to slope mass rating (SMR), Chinese slope mass rating (CSMR) and the continuous slope mass rating (CoSMR). A comparative analysis was also carried out among the findings of various rockmass characterization techniques to predict the stability of the road cut slopes along NH-44A highway.

Rock Slope Stability Assessment Using Geomechanical Classification and its Application for Specific Slopes along Kodaikkanal-Palani Hill Road, Western Ghats, India

ABSTRACT Linear infrastructure networks like roads play a vital role in the socio-economic development of hill towns centered on tourism. Stability of the slopes along the hill roads are therefore a major concern and slope failures lead to disruption of traffic and loss of property/life or both. This study analyses the stability of cut-slopes along the Kodaikkanal – Palani hill road in the Western Ghats, India using rock mass classification systems like rock mass rating (RMR), slope mass rating (SMR) and continuous slope mass rating (CSMR). These geomechanical classifications provide a preliminary assessment of rock quality based on rock strength, discontinuity properties, hydrogeological condition of the slopes and slope stability based on the inherent rock strength parameters, discontinuity orientation and method of excavation. The results showed that both rock quality and discontinuity orientation contribute to type of failure in rock slopes with RMR > 40. SMR results are conservative while CSMR classification is matches more closely to the failures obtained from the field survey. CSMR classification represents continuous slope stability conditions and hence are more suitable for development of spatial database. Cutting of roads, thereby, steepening slopes has a definite influence on the stability of slopes.

Stability assessment of Himalayan road cut slopes along National Highway 58, India

Himalaya is one of the most tectonically and seismically active mountain chains in the world having complex geological and geotechnical conditions. The Himalayan region experiences frequent slope failure posed due to various natural and anthropogenic causes. Slope instability issues have consequent effects on the socio-economic development of the people and the region in a large scale. In the present study, stability analysis of vulnerable road cut slopes along NH-58 from Rishikesh to Devprayag in the Lesser Himalayas has been conducted. Critical slopes were identified by considering the geological and the geotechnical complexities within the region. Rock mass characterisation techniques have been employed for slope stability assessment. Rock mass rating (RMR), slope mass rating (SMR) and continuous slope mass rating (CSMR) methods have been applied to evaluate different stability levels of rock mass along the highway. Spatial variation of stability classes using RMR, SMR and CSMR techniques has been analysed on geographic information system (GIS) tool. Kinematic analysis technique was also employed to identify the different modes of structurally controlled failures in jointed rock mass. Accordingly remedial measures have been suggested to improve slope stability.

Geotechnical Investigation on Slopes Failures along the Mughal Road from Bafliaz to Shopian, Jammu and Kashmir, India

ABSTRACT In this paper, the results of geotechnical investigations on the slope stability condition carried along the historical Mughal road (an important economic corridor of the state) from Bafliaz (Jammu province) to Shopian (Kashmir province) linking NH144 and NH444 respectively is presented. The basic rock mass rating (RMRb), slope mass rating (SMR) techniques (both discrete and continuous functions) with kinematics analysis was applied to analyse the rock mass and slope conditions at 20 selected sites. The RMRb results obtained reveal the slopes can be categorized into very good (5%), good (55%) and fair (40%) whereas SMR results reveal that the slopes are partially stable (50%), unstable (30%) and completely unstable (20%) with probable planar failure mode (20%), toppling failure mode (27%) and wedge failure mode (53%). The discrete and continuous SMR index reveals maximum variation in the end results within an average difference of 4.7 ±6. The kinematic analysis results support inter dependency of RMRb, SMR and critical joint-slope orientation relationships.

The Assessment of Slope Stability along NH-22 in Rampur-Jhakri Area, Himachal Pradesh

Abstract: The present paper demonstrates the assessment of slope stability analysis between Rampur to Jhakri road section along National Highway (NH-22), Himachal Pradesh, India. The different types of slope failures have affected most part of slopes which causes considerable loss of life and property, inconveniences such as disruption of traffic along highways. The poorly designed rock slopes for road widening or construction purposes may weaken the stability of the slopes. A detail field investigation has been carried out to collect the representative rock samples for determination of physico-mechanical properties of rock and joint data for kinematic analysis. The rocks exposed in the area are highly jointed quartzite and quartz-mica schist of Rampur-Larji Group of Palaeoproterozoic age. The continuous slope mass rating (CSMR) technique has been applied for the assessment of slope stability analysis at five vulnerable locations and the results shows slopes are partially stable to unstable. Kinematic analysis mainly shows wedge type of failure along with few toppling and planar failures. The existing slope required immediate treatment to prevent the failure for its long term stability.

Rock Slope Stability Analysis along NH-44 in Sonapur Area, Jaintia Hills District, Meghalaya

Abstract: Occurrences of landslide are most common and critical issue in North-East India. The various types of slope failures have been affected most part of slopes and road section between Malidor to Sonapur area (approx 30 Km) along NH-44 within Jaintia hills district, Meghalaya, India. These slope failures causes considerable loss of life and property along with many inconveniences such as disruption of traffic along highways. The unscientific excavations of rock slopes for road widening or construction purposes may weaken the stability of the slopes. The rocks exposed in the area are highly jointed sandstone and shale of Barail Group of Oligocene age. The Sonapur landslide is most dangerous and destructive rock fall-cum debris flow. The present study includes the kinematic analysis of the slope to assess the potential failure directions as the rocks are highly jointed in some parts of road cut sections. The continuous slope mass rating (CSMR) technique has been applied for slope stability analysis at five vulnerable locations. Kinematic analysis indicates mainly wedge type of failure along with few toppling and planar failures. These failure required immediate treatment to prevent the slide and long term stability of the slope.