• T N SINGH

Articles written in Journal of Earth System Science

• Qualitative stability assessment of cut slopes along the National Highway-05 around Jhakri area, Himachal Pradesh, India

Several deformation phases in tectonically active Himalayas have rendered the rock masses very complex in terms of structure, lithology and degree of metamorphism. Again, anthropogenic activities such as roads, tunnels and other civil engineering constructions have led to a state of disequilibrium which in many cases, results in failure of rock masses. National Highway-05 around Jhakri area in India is a major connecting route to the China border in the hilly terrains of the state Himachal Pradesh. It cuts through the Himalayan rocks and has a hazardous history of landslides destroying human lives and interrupting communication very frequently. As a contribution towards the mitigation process, a study has been carried out along the highway to analyse kinematic stability and qualitative estimation of rock mass condition through rock mass classification systems. The kinematic analysis shows that the rock slopes are prone to planar and wedge failure. Rock mass rating for most of the locations lies between 7 and 34, representing a poor rock mass quality (Class IV), whereas slope mass rating is more disperse and ranges from 11 to 52 for most of the slopes (Class III, IV and V).

• Geo-engineering classiBcation 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.

• Stability analysis of road cut slope near Devprayag in Lesser Himalaya, India

The slope instability issues in Himalayan terrain is drastically increasing due to variety of anthropogenic activity and rapid urbanization. Road and highway networks in mountainous regions are the main source in remote parts of hilly terrain for the transportation as well as all sorts of socio-economic features. The study of slope stability in these hilly regions along the highways and roads are major concern, where slope instability caused transportation problems, death and injury of human, loss of their properties and also environmental degradation. Present article exposed the slope instability analysis for the two typical slopes along National Highway (NH-7), between Devprayag and Mulyagao in Uttarakhand, where the Highway goes up to the holy shrine of Kedarnath and Badrinath. The vulnerable slopes are numerically simulated using limit equilibrium method (LEM) and finite element method (FEM) for dry and saturated condition. The comparative analysis of factor of safety for LEM and FEM results show good correlation, i.e., 1.6–2.4% variance in dry condition and in saturated condition the LEM and FEM results show 11–13% variance. The finite element simulation has also assessed the principal stresses and displacement vector, which gives more understanding to identify and reveal the slope stability issues in analogous morphology. The result shows that both the slopes are in critical condition and prone to failure in rainy season due to exertion of water in intensely fractured rocks.

• Slope stability analysis of road cut slopes along NH-58 in Alaknanda Valley from Dhari Devi to Rudraprayag, Uttarakhand, India

Slope stability assessment of vulnerable slopes was conducted along National Highway 58 (NH-58) from Dhari Devi to Rudraprayag (${\sim}$17 km), Uttarakhand. Kedarnath devastation in June, 2013 due to flash floods has made road cut slopes along the Alaknanda River vulnerable, which has a history of frequent landslides particularly at Kaliasaur (sites K1, K2, K3). At Kaliasaur landslide (site K1), the instability is mainly controlled by the combination of pre-existing tectonic fracturing, plunging fold, structural damage zones formed due to the passage of regional Kaliasaur Fault and at site K3, fault gouge is found due to shearing of quartzite. A total of 35 road cut slopes were investigated along NH-58 and kinematic analysis of joint data shows that 18 slopes are prone to planar failure, 7 for wedge failure and 8 for toppling failure. Slope mass rating (SMR) and continuous SMR show that 18 slopes are vulnerable with 6 slopes falling under the class III category (partially unstable), 9 slopes under class IV (unstable) and the rest of 3 slopes are completely unstable fall under class V causing landslides on NH-58. Maps with location of stable, partially stable, unstable and completely unstable sites are formed to take infrastructure projects at stable zones.

$\bf{Highlights}$

$\bullet$ Kaliasuar fault causes active landslides along NH-58, Uttarakhand.

$\bullet$ Maps with location of stable sites are provided for infrastructure projects.

$\bullet$ Instability at Kaliasaur Landslide is caused by plunging fold, pre-existing tectonic fracturing.

$\bullet$ Conducted kinematic analysis and geo-mechanical classification based on CSMR of 35 slopes in the study area.

• # Journal of Earth System Science

Volume 131, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019