Rock Cut Slopes Research Articles

The life span and influencing factors of metal mesh in artificial soil on railway rock-cut slopes in humid areas

The stability of slope is strengthened by the metal mesh. The studies of the life span and influencing factors of metal mesh in the artificial soil in humid areas will guide ecological restoration of rock-cut slopes in Southwest China. Due to metal corrosion, the fixation function of the metal mesh could last for 10 years. The factors of soil contents, soil electrochemical properties and soil bacteria not only changed with the vegetation succession but also weakened the effect of the metal mesh on soil fixation for slope protection. The potential gradient, chloride ion content, sulfate ion content and water content were the main influencing factors for metal mesh corrosion during the vegetation restoration stage from 0 to 5 years, while the corrosion potential, potential gradient, chloride ion content, and water content were the main influential factors for metal mesh corrosion during the vegetation restoration stage after 11 years. At different vegetation restoration stages, the soil bacteria contained different dominant species, which had spatial heterogeneity, and the heterogeneity of the soil bacteria was another factor influencing the corrosion of the buried metal mesh. Meanwhile, the plant root as a soil fixation function strengthened with time, and 8 years later, the local woody plants gradually migrated to form a community dominated by multiple woody species. It is the first time that the life span of a metal mesh under the artificial soil of rock-cut slopes and factors affecting the different corrosion stages of the metal mesh in a humid area have been judged. The fixation function of plant root gradually replaces metal mesh, and main factors affecting the process include soil contents, soil electrochemical properties and soil bacteria. The research on corrosion factors of metal mesh under artificial soil for rock-cut slopes will contribute towards reducing the environmental risk of ecological restoration.

How backfill soil type influencing on Cd and Pb migration in artificial soil on railway rock-cut slopes

Cadmium (Cd) and lead (Pb) that accumulates in the surface soil of railway rock-cut slopes may migrate to nearby croplands. It is important to determine whether backfill soil type influences the transportation of Cd and Pb in the surface soil. Representative rock-cut slopes, backfill soil of 100% rock fragments, 100% agricultural soil, and 50% agricultural soil and 50% rock fragments (n = 2 for each type) were selected. The pollution and migration levels of Cd and Pb and the soil quality and erodibility were investigated. The soil concentrations of Cd and Pb on the rock-cut slopes were much higher than those of China soil quality standard. Soil erosion was the most important factor that influences the migration of Cd and Pb in the slopes. Increasing the percentage of agricultural soil in the backfill soil resulted in decreasing the diffusion of Cd and Pb by reducing soil erosion. The backfill soil affected the soil quality and erosion durability, which, in turn, affected the transportation of Cd and Pb in the runoff. The soil quality index (SQI) accurately reflects the soil quality and can serve as an indicator of the migration of Cd and Pb on the surface soil of the slopes. Therefore, agricultural soil was more appropriate to use as a backfill soil in slope revegetation practice than was the rock fragment, which was helpful for decreasing the environmental risk of Cd and Pb on the slopes.

Topographic aspect affects the vegetation restoration and artificial soil quality of rock-cut slopes restored by external-soil spray seeding

External-soil spray seeding (ESSS), a technique of spraying artificial soil materials onto bare slopes for vegetation cover construction, has been widely used to restore rock-cut slopes. However, studies on the effect of the practical application of this technique on different topographic aspects have been rarely performed. In this study, two topographic aspects, namely, north-facing versus south-facing, were investigated under two railway lines, and two local natural slopes (north-facing versus south-facing) were selected as references. Vegetation and soil conditions, which are paramount aspects of ecological restoration assessment, were characterized in terms of the richness and diversity indices, vegetation canopy cover, basic soil physico-chemical properties, and structural characteristics of these slopes. Results showed that (1) the topographic aspect significantly affected the vegetation restoration and artificial soil quality of rock-cut slopes restored by ESSS; (2) the ecological restoration effect of north-facing slopes were better than that of south-facing slopes; and (3) the vegetation and soil conditions of natural slopes were better than those of rock-cut slopes. Therefore, additional scientific management measures should be implemented to promote the ecological restoration of rock-cut slopes, especially for south-facing slopes.

Effects and mechanisms of revegetation modes on cadmium and lead pollution in artificial soil on railway rock-cut slopes

Artificial soil on railway rock-cut slopes may be considerably contaminated with cadmium (Cd) and lead (Pb), which may migrate to nearby croplands and pose substantial risks to human and animal health. We investigate the influence of three types of revegetation modes – herbs (HS); herbs and shrubs (HSS); and herbs, shrubs, and trees (HSTS) – on the transportation of these heavy metals in soils. Six representative rock-cut slopes were chosen, and the vegetation, pollutant concentration, phytostabilization, and simulated rainfall were investigated. The results indicated that Cd posed a considerable ecological risk, while Pb posed a low ecological risk in the artificial soil. The erosion of artificial soil on the slopes played a primary role in the migration of Cd and Pb, because 87–91% of Cd and 85–89% of Pb was lost in sediments. Revegetation modes significantly affected the transportation of Cd and Pb. HSTS controlled a lot of Cd in their dominant plants among the three revegetation modes. HSTS not only decreased enrichment factor (EF) and ecological risk (Er) values of Cd in the soils, but also decreased runoff, sediment and cumulative migrated Cd and Pb. The relationships among multi-factors were analyzed by stepwise mediation effect test and the results indicated that root weight density, aboveground biomass and immobilization of dominant plants for Cd and Pb were important direct factors which influenced the transportation of Cd and Pb. Overall, HSTS has proven to be beneficial in controlling the migration of Cd and Pb to croplands near the slopes and reducing their environmental risk. These results can offer a tested and implementable solution for mitigating the risks posed by these pollutants around the quickly expanding railways in the study region.

Enzyme activity and microbial biomass availability in artificial soils on rock-cut slopes restored with outside soil spray seeding (OSSS): Influence of topography and season

Large-scale railway construction has resulted in large areas of bare-cut-slope, and outside soil spray seeding (OSSS), a frequently used technique, has been adopted for slope restoration for many years. However, compared with natural slope soils, the quality of artificial soils on rock-cut slopes is low. Enzyme activity and microbial biomass are the main indices used for estimating soil quality; thus, our objective was to explore the influence of slope position, slope aspect, and season on two important factors that positively influence the plant growth capability in artificial soil. Further, we suggest modifications of the proportions of OSSS ingredients, not only to manage cut slopes more economically but also to provide a new framework for managing desertification.We chose a bare-cut-slope that had been restored five years ago near the Suiyu Railway (Chongqing-Suining), in Sichuan Province, China, as our study plot. Soil samples were collected at a depth of 10 cm. We conclude that natural slopes exhibited higher urease, sucrase, and catalase activity and higher microbial biomass than cut slopes. The protease and polyphenoloxidase enzyme activities and the microbial biomass were higher on the cut slopes in the months of October and January, with the highest protease activity in October, and the highest polyphenoloxidase activity in January. The enzyme activity and microbial biomass were always lower on lower slopes, with the exception of polyphenoloxidase activity. The slope aspect influenced soil enzyme activity, resulting in higher activity on north-facing slopes than on south-facing slopes. These results provided scientific support for artificial revegetation methods in an ecological context.

The Stability of Metasedimentary Rock in Ranau, Sabah, Malaysia

DOI: 10.17014/ijog.5.1.23-31The aim of this paper is to determine the stability of slopes and to propose preliminary rock cut slope protection and stabilization measures for Paleocene to Middle Eocene Trusmadi Formation along Marakau-Kigiok in Ranau, Sabah, Malaysia. The rock of Trusmadi Formation is slightly metamorphosed and dominated by interbeds of sandstone with quartz vein (metagreywacke), metamudstone, shale, slate, sheared sandstone, and mudstone. The rock unit can be divided into four geotechnical units namely arenaceous unit, argillaceous unit, interbedded unit, and sheared unit. Twelve slopes were selected for this study. Geological mapping, discontinuity survey, kinematic analysis, and prescriptive measure were used in this study. Results of this study conclude that the potential modes of failures are planar and wedge. Terrace, surface drainage, weep holes, horizontal drain, vegetation cover, wire mesh, slope reprofiling, and retaining structure were proposed protection and stabilization measures for the slopes in the studied area.

Overhanging rock slope by design: An integrated approach using rock mass strength characterisation, large-scale numerical modelling and limit equilibrium methods

Overhanging rock slopes (steeper than 90°) are typically avoided in rock engineering design, particularly where the scale of the slope exceeds the scale of fracturing present in the rock mass. This paper highlights an integrated approach of designing overhanging rock slopes where the relative dimensions of the slope exceed the scale of fracturing and the rock mass failure needs to be considered rather than kinematic release of individual blocks. The key to the method is a simplified limit equilibrium (LE) tool that was used for the support design and analysis of a multi-faceted overhanging rock slope. The overhanging slopes required complex geometries with constantly changing orientations. The overhanging rock varied in height from 30 m to 66 m. Geomechanical modelling combined with discrete fracture network (DFN) representation of the rock mass was used to validate the rock mass strength assumptions and the failure mechanism assumed in the LE model. The advantage of the simplified LE method is that buttress and support design iterations (along with sensitivity analysis of design parameters) can be completed for various cross-sections along the proposed overhanging rock sections in an efficient manner, compared to the more time-intensive, sophisticated methods that were used for the initial validation. The method described presents the development of this design tool and assumptions made for a specific overhanging rock slope design. Other locations will have different geological conditions that can control the potential behaviour of rock slopes, however, the approach presented can be applied as a general guiding design principle for overhanging rock cut slope.

Failure of a Rock Slope Ten Years after Excavation

In the present study, a rock cut slope in Chongqing of China, which failed suddenly about ten years after excavation, was reported. The survey results after failure indicated that the rock masses of the rock slope were highly fractured and heavily weathered, the critical slip surface was composed of three connected discontinuities from the toe to top of slope. The factors resulting in the failure of rock slope were mainly initial excavation and weathering process. The initial excavation removed original supporting role of the excavated rock masses at the toe of the slope to the upper unexcavated rock masses, and broken the original ground stress balance. The physical and chemical weathering after the initial excavation cracked progressively the rock masses, deteriorated the mechanic properties of the rock masses, and changed the stresses and strains in the rock slope. The stability of high artificial rock slope during operation should be paid attention to. The characteristics of geological structure, unloading induced by excavation, and weathering have important effects on the evolution for deformation of artificial rock high slope.

Mechanism Analysis of the Failure for a Safe Jointed Rock High Slope: Tectonic Structures and Damage

Tectonic structures and tectonic damage of rock slope have an important effect on its failure mode, but it isn’t always paid attentions in actual engineering works. In the present study, a rock cut slope in Chongqing of China was reported. The survey results during the construction of the expressway indicated it should be safe, but it failed at last. The main reason is that tectonic tectonics and tectonic damage are not adequately taken into account in the design of this slope. The strong folds make the slope rock mass broken. Three groups of joints in the rock masses of the rock slope provide geometric conditions for landslides, and the further possible failure of the rock cut slope may follow the three group joints. The excavation change the stress environment of the slope and promote the destruction of the slope. Due to weathering processes, the integrality and shearing strength of the rock masses were reduced. The time-effect of excavations and weathering-effect are interacting with each other. Eventually, the slope not only slipped along the structural surface, but also produced plastic deformation damage. This indicates that in the design of the slope, the tectonic structures and tectonic damage must be fully considered, time effect is a factor which cannot be ignored.

SMR and Kinematic Analysis for Slope Instability along Bodi-Bodimettu Ghat section, Tamil Nadu

ABSTRACT This study evaluates slope stability of 19km stretch Bodimettu ghat section, Theni, Tamil Nadu. The study involves 107.8km to 117.5km stretch by dividing it into two zones - Kaththuparai and Bodimettu slope. These two sections are considered for slope stability studies. In this study, analysis of the rock slope stability was performed using Modified SMR technique. Hoek and Bray (1981) analysis have been used for rock cut slopes. 12 rock slopes were identified in Kaththuparai section and four slopes in Bodimettu section. The detailed field investigations were carried out to collect data required for RMR and SMR calculation and SMR was calculated for each section. As per Hoek and Bray (1981) stereographic projection methods, FOS was calculated. In this study, sections R1 and R2 fulfill wedge conditions and R1, R2, R5, R7, R9, R10, R11, R12, R13, R14 and R16 are suitable for planar and stereographic analysis. The details are furnished in this paper. The planar analysis shows that, FOS for the sections R2/J2, R5, R9, R10, and R11/J3 was < 1, and stereographic projection study shows that sections R2, R5, R7, R9, R10, R11/J3 and R13 are present in unstable zone.

Identification of Rock Slope Discontinuity Sets from Laser Scanner and Photogrammetric Point Clouds: A Comparative Analysis

Discontinuities play a key role in the mechanical, hydraulic and deformational behaviour of rock masses, frequently having a considerable influence on the stability of rock slopes. They can be characterized by several geometric parameters as the orientation, persistence, spacing, etc. Although orientation has been traditionally measured through well-known techniques as a compass, more recent remote sensing techniques such as 3D laser scanning allow deriving both strike and dip direction of discontinuities. The novel SfM (Structure from Motion) technique, which is much less expensive than 3D laser scanning, is becoming mainstream within the research community. This paper examines the generation of 3D point clouds of a rock slope obtained from both, 3D laser scanning and SfM techniques, and their application to the extraction of the orientations of the main discontinuity sets. To this aim, a selected sector from a cretaceous sedimentary rock cut slope placed in Alicante (Spain) is analyzed using both photogrammetric and terrestrial laser scanner (TLS) point clouds. Using ground control points extracted from printed targets scanned by means of TLS provided very accurate coordinates. As a result of this, the obtained adjustment error was minor than 3 mm. The comparison of the resulting point clouds shows a good correlation when the surface is orthogonal to the line of sight. On the contrary, the SfM dataset showed inaccuracies on sub-horizontal and oblique surfaces. Finally, a geometrical analysis was performed by means of DSE software. Three discontinuity sets were extracted from both point clouds. However, one more was extracted from the TLS dataset, but not from the SfM dataset.

Parametric evaluation of shear strength parameters on the stability of cut slope: a case study from Mahabaleshwar road section, India

Stability of rock cut slopes depends upon the type of material, discontinuity attributes and geometry present in any location. Although, gravity remains the constant important factor in dictating the slope failure but other parameters like shear strength and available shear stress along the slope also decides the stability of the slopes to great extent. The strength of the material comes from the internal bonding between the mineral grains, contact between the particles and the ability of the material to respond to the stress conditions. Variation of these material attributes fluctuate the cohesion and angle of internal friction that constitutes the most important properties in defining the strength of any material. Rock resists shear stress by these two internal mechanisms. Numerical simulation by Finite Element Method technique is attempted for assessing the stability cut slope. An attempt has been made in this study to document the behavior of strength of the material in terms of stability of slopes by parametric study of cohesion and internal friction. This study carried to understand how the factor of safety changes with reference to change in cut slope height, cohesion and internal friction of the discontinuities that attributes the shear strength of discontinuities. The study is based on Finite Element Modeling (FEM). From the study it is found that factor of safety has strongly proportional relation with cohesion and internal friction but shown inversely proportional relation with height of cut slope.

Cut slope stability assessment along ghat road section of Kolli hills, India

In the present study, cut slope stability assessment along ghat road section of Kolli hills was carried out by using various geotechnical parameters of rock and soil slope sections and structural kinematics of major discontinuities is presented. The rock slope (RS) stability assessment was carried out using Rock Mass Rating basic (RMRbasic) and Slope Mass Rating (SMR) classification systems. The type of failure and their Factor of Safety (FOS) for individual RS was calculated using Hoek and Bray method. In the case of soil slopes (SS), the FOS was calculated using Circular Failure Chart (CFC) and Limit Equilibrium (LE) methods. The input data for the slope stability analyses were collected through extensive field work followed by stereonet plotting and laboratory test. There are six rock slope sections, and five soil slope sections were taken into consideration for the cut slope stability analyses. The area depicts class II (RS-1, 2, & 6) and class III (RS-3, 4, & 5) of RMR classes. The SMR result depicts for RS-1, RS-2, and RS-6 are 64.40, 60.02, and 60.70, respectively, and falls in class II stable condition. The SMR values of RS-3 and RS-5 were 44.33 and 57, respectively, and come under the class III partially stable condition. The RS-4 with SMR value of 17.33 falls under the class I completely unstable condition. The FOS of planar failure case indicates that RS-3 (FOS = 0.22) is more unstable, while all other sections are having greater than 1 FOS. The calculated FOS values using CFC method reveals that the FOS is very close to 1 for all the SS sections that fall under completely saturated condition which indicates that these slope sections may fail during heavy rainfall. In LE method, the sections SS-3 and SS-4 are unsafe under partially and completely saturated (natural slope) condition. In average slope condition, all the SS sections are unsafe under partially or completely saturated conditions. The facets 2, 3, 4, and 5 required mitigation measures, to improve the stability of slopes. Site-specific mitigation measures were suggested for partially or completely unstable rock and soil cut slopes.

Failure of a rock slope 16.5 years after excavation in repeated strata of sandstone and mudstone

The present study focuses on failure of a rock slope excavated in the autumn of 1997 and located in the repeated strata of sandstone and mudstone in Chongqing of China. The rock slope failed suddenly on April 28, 2014. The elapsed time from excavation to failure is about 16.5 years. The failure was sudden and unexpected seemingly, but it was mainly resulted from the initial excavation and the subsequent weathering in the long term. The initial excavation in 1997 as a reason why the rock cut slope failed was undoubted, because the excavation broke original ground stress balance, resulted in inducement or expansion of cracks and induced deformation and looseness of local rock masses. The weathering process, especially physical weathering process in the long term (16.5 years after excavation), is the most important reason of the failure, because it resulted in disintegration of material on slope surface and induced reduction of strength in the interior of the slope. Water, as a key factor speeding up the weathering process, weakened mechanical properties of rocks and discontinuities and urged formation of argillation intermediate layer. Based on the analyses of failure modes and corresponding factors of safety, an integrated stabilization system on the rock slope was put in place.

Assessment of rock slope stability by probabilistic-based Slope Stability Probability Classification method along highway cut slopes in Adilcevaz-Bitlis (Turkey)

Rock slope stability is of great concern along highway routes as stability problems on cut slopes may cause fatal events as well as loss of property. In rock slope engineering, stability evaluations are commonly performed by means of analytical or numerical analyses, principally considering the factor of safety concept. As a matter of fact, the probabilistic assessment of slope stability is progressively getting popularity due to difficulties in assigning the most appropriate values to design parameters in analytical or numerical methods. Additionally, the effect of heterogeneities in rock masses and discontinuities on the analysis results is minimized through the probabilistic concept. In this study, slope stability of high and steep sedimentary rock cut slopes along a state highway in Adilcevaz-Bitlis (Turkey) was evaluated on the basis of probabilistic approach using the Slope Stability Probability Classification (SSPC) system. The probabilistic assessment indicates major slope stability problems because of discontinuity controlled and discontinuity orientation independent mass movements. Almost all studied cut slopes suffer from orientation-independent stability problems with very low stability probabilities. Additionally, the probability of planar and toppling failures is significantly high with respect to the SSPC system. The stability problems along the investigated rock slopes were also verified by field reconnaissance. Remedial measures such as slope re-design and reinforcement at the studied locations should be taken to prevent hazardous events along the highway. On the other hand, the probabilistic approach may be a useful tool during rock slope engineering to overcome numerous uncertainties when probabilistic and analytic results are compared.

Rockfall analysis along transportation corridors in high hill slopes

The paper discusses the problems pertinent to rockfall activities in highly jointed rock cut slopes, excavated without detailed geotechnical and geological investigations along the right bank of river Sutlej, Luhri, Himachal Pradesh, India. The cut slopes are near vertical to sub-vertical and overhangs are ubiquitous at several locations. Initially, probable zones of slope failure were identified from field inspection and kinematic analysis. The study then uses 2D rockfall analysis for estimating loss of energy due to the impact of falling blocks on the slope face and subsequently on the road. Several parameters were also assessed from the study viz. bounce height, travel distance, kinetic energy and translational velocity. The result from rockfall analysis shows that the energy and velocity achieved by the falling blocks are considerably high, capable enough to cause severe damage. In relation to energy and velocity, bounce height achieved is not very large. Because of removal of trees from the slopes face and no measures to capture falling blocks, the problems have been aggravated and therefore, most of the rock covers very large distance to reach up to the valley crossing the roadways endangering travelers and infrastructures. Based on the results, preventive measures have been suggested to prevent future rockfall hazards.

Geomechanical classification scheme for heterogeneous Crocker Formation in Kota Kinabalu, Sabah, Malaysia: An update

Geomechanical classification scheme for heterogeneous Crocker Formation in Kota Kinabalu, Sabah has been proposed in 2009 and known as Modified Slope Mass Rating (M-SMR). M-SMR was used to characterize and to propose preliminary rock cut slope design such as slope stabilization and protection measures and recommendation levels for design model review and slope remapping by suitable engineering geologist or geotechnical engineers. The ‘Lithological unit thickness’ approach, RQD method, weighted average of discontinuity set spacing, weighted average, statistical mode and new approach of adjustment factor (NAAF) methods were used to evaluate the parameters in M-SMR. The classes in MSMR scheme consists of class I (very good) to class VI (extremely bad). Local trimming, slope re-profiling, weep hole, horizontal drainage, concrete dentition or buttress, rock bolting or dowel, wire mesh or rope nets, reinforce shotcrete and benching are proposed slope stabilization and protection measures. Normal to detailed Design Model Review (DMR) and slope remapping are recommended to highly recommended by engineering geologist or geotechnical engineers to expert engineering geologist or geotechnical engineers for class I to class VI, respectively.

Impact of Soil Composition and Electrochemistry on Corrosion of Rock-cut Slope Nets along Railway Lines in China.

Taking the slope of Suiyu Railway to study, the research separately studied soil resistivity, soil electrochemistry (corrosion potential, oxidization reduction potential, electric potential gradient and pH), soil anions (total soluble salt, Cl−, SO42− and ), and soil nutrition (moisture content, organic matter, total nitrogen, alkali-hydrolysable nitrogen, available phosphorus, and available potassium) at different slope levels, and conducted corrosion grade evaluation on artificial soil according to its single index and comprehensive indexes. Compared with other factors, water has the biggest impact on the corrosion of slope protection net, followed by anion content. Total soluble salt has the moderate impact on the corrosion of slope protection net, and stray current has the moderate impact on the corrosion of mid-slope protection net. Comprehensive evaluation on the corrosive degree of soil samples indicates that the corrosion of upper slope is moderate, and the corrosion of mid-slope and lower slope is strong. Organic matter in soil is remarkably relevant to electric potential gradient. Available nitrogen, available potassium and available phosphorus are remarkably relevant to anions. The distribution of soil nutrient is indirectly relevant to slope type.

Effects of different backfill soils on artificial soil quality for cut slope revegetation: Soil structure, soil erosion, moisture retention and soil C stock

Large-scale railway/highway construction in hilly areas in China has created a number of bare rock cut slopes. Artificial soil is often sprayed onto those slopes to promote revegetation. The artificial soil used is a mixture of backfill soil, humus, straws, soluble chemical fertilizer, composite material and plant seeds. The backfill soil is the most important component of the artificial soil. Knowledge of the changes in the artificial soil quality induced by backfill soil is important for the management of the revegetation of rock cut slopes. This study was conducted to assess the effects of different backfill soils on soil quality parameters and slope restoration parameters, including the particle size distribution, water-stable aggregates, soil organic carbon (SOC), organic carbon fractions, soil water characteristics (SWC), plant coverage, Margalef index and Shannon-Wiener diversity index. In experiment one, the treatments included slopes backfilled with rock fragment (RF), slopes backfilled with agricultural soil (AS) and a natural slope (NS). In experiment two, the treatments were experiment plots with different proportions of agricultural soil to rock fragments. Soils were sampled from the surface layer (0-5 cm) of the slopes. The results indicated that the backfill soil significantly affected the soil structure. RF increased the percentage of large particles (>0.25 mm) and decreased that of microparticles (<0.25 mm). The fractal dimension and the water-stable aggregate content of RF were smaller than those of AS. Moreover, RF exhibited the highest soil destruction rate of soil aggregates among the three treatments. Our findings also indicate that RF conserved a smaller percentage of SOC in less degraded forms (coarse and fine particulate organic matter (POM) fractions) than AS management. At almost all of the soil suctions studied, AS retained more volumetric water content (theta(v)) than RF or NS. The AS soil contained 17.3% more plant available water (PAW) than the RF soil. The plant coverage, Margalef index and Shannon-Winner were investigated to evaluate the restoration of the rock cut slopes compared with natural slopes. The three parameters of the RF were all smaller than those of the AS and NS. Overall, RF exhibited poorer soil structure and hydrological properties, increasing the risk of surface runoff and soil erosion because it had not undergone sufficient soil-forming processes and lacked SOC. Therefore, the use of rock fragments as backfill soil was not helpful for maintaining artificial soil with sufficiently high quality for the slope revegetation. (C) 2015 Elsevier B.V. All rights reserved.

Rockfall Hazard Rating System along SH-72: a case study of Poladpur–Mahabaleshwar road (Western India), Maharashtra, India

Construction of railways, highways and roads around steep slopes is a challenging assignment and require special investigations by geologists and geotechnical engineers that help to identify critical slopes. Rockfall Hazard Rating System for India (RHRSI) is a modified scheme for Indian subcontinent and used to define overall stability of slopes in mountainous region or rock cut slopes. Once this rating system identifies critical zones, proper protection measures can be applied to prevent rockfalls. In this article, RHRSI is adopted to identify slopes, prone to rockfalls so that proper preventive measure can be proposed to mitigate loss. State Highway-72 (SH-72) connecting Poladpur to Mahabaleshwar, is an important transportation corridor supporting high vehicle traffic within the well-known tourist area is chosen for rockfall hazard rating. Field observations show that up to 15 km corridor from Mahabaleshwar town has frequent rockfall problems with two most rockfall locations situated at about 12 and 6 km from Mahabaleshwar town. Also, an attempt has been made to focus on risk-consequence analysis for rockfall locations. To this aim, the RHRSI is applied to SH-72 corridor on two locations which are identified as very prone to rockfall hazard.