http://pucir.inflibnet.ac.in:8080/jspui/handle/123456789/550 2026-04-30T17:19:09Z http://pucir.inflibnet.ac.in:8080/jspui/handle/123456789/1016 Title: Preliminary investigation on Cyclone Remal‑in‑ duced landslides in Aizawl, Mizoram, Northeast India, on the 28th of May 2024 Authors: Lawmkima, H Abstract: On the 28th of May 2024, Cyclone Remal brought intense rainfall, triggering catastrophic landslides in Aizawl, the state capital of Mizoram, northeast India. The region is prone to landslides due to its fragile geology and steep terrain, and it has experienced severe damage, including loss of life, destruction of property, and disruptions to essential services. It had a severe impact on society, resulting in 34 fatalities with 33 bodies recovered and affecting 72 families, leading to the evacuation of 54 houses within Aizawl. It also affected the cemeteries of four localities. Among the numerous landslides observed during the field survey, fourteen sites were selected for the study. This study aims to assess the social impacts of these landslides and analyze the failure mechanism involved to guide future disaster preparedness and mitigation strategies. In addition to the information gathered from the government and social media, a field-based method of investigation was used in this study. The methods involve site visits, interviews with local communities, and an analysis of geological, geotechnical, and rainfall data. Geotechnical investigations were conducted at nine sites of the studied areas, all involving rock slides. An investigation was done into the stability of the affected rock slopes, including kinematic analysis, uniaxial compressive strength test (UCS), rock mass rating (RMR), continuous slope mass rating (CoSMR), and slake durability test. The field survey and interviews determined that the landslides caused 25 fatalities, with ten houses and twenty-two vehicles damaged in the Melthum and Hlimen areas. The total property loss was estimated to be Rs.3.4 crores. Landslides displaced more than 300 graves. Most of the probable slope failure observed using kinematic analysis show planar and wedge types of sliding. The studied rock mass of the slope falls under the poor to fair class in RMR ratings and ranges from partially stable to completely unstable in the CoSMR assessment. The rock collected from nine locations of the study landslide area shows medium to high durability and a strength of 14.8 to 22.6 MPa using slake durability and uniaxial compressive strength test (UCS), respectively. The study concludes that while intense rainfall was the primary cause, contributing factors like lack of expert consultation on slope modifications, weak rock mass characteristics, steep slopes, inadequate infrastructure planning, and fragile geological conditions increased the likelihood of slope failure. It seriously impacts society, resulting in many lives and infrastructure loss, economic hardship, and psychological stress, especially among those living in landslide areas. The findings emphasize the necessity of comprehensive land-use planning, improved infrastructure resilience, and coordinated disaster preparedness efforts to mitigate the risk of future landslides. 2025-02-01T00:00:00Z http://pucir.inflibnet.ac.in:8080/jspui/handle/123456789/551 Title: Geotechnical investigation of landslide near Sairang Village in Aizawl district, Mizoram, India Authors: Lawmkima, H Abstract: The investigated landslide area is about 5.4 km north of Sairang village on Aizawl-Silchar road (NH-54). The length, breadth and height of slide are 110 m, 20 m and 70 m respectively. The dominant rock types exposed in the study area are sandstone, siltstone and shales and their admixtures in various proportions. The main factors for the instability of this area stems from the intersection of two sets of joints dividing the rock beds into varying dimensions and the presence of bedding shears and clay pockets/beds with swelling and shrinkage properties, decrease in the shear strength of overburden and bed rocks during rainy season due to water saturation and erosion of shaly layer by scouring action and a high hill slope. Remedial measures such as; lined catch water drains and chute for channeling surface water flow along the hill slope; lining of side drain to prevent toe erosion and also to prevent water percolation through debris. Sealing/filling of ground fractures/cracks with clayey material; breast and retaining structures to prevent toe erosion are suggested. 2018-01-01T00:00:00Z