Skip to main content

Problems of Lesser Himalaya with mitigation

Short answer

The Lesser Himalaya faces landslides, rock fall, weak foliated rocks, karst cavities, and seismic hazards. Mitigation includes gentle cut slopes, retaining structures, drainage, rock bolts, shotcrete, bio-engineering, grouting, and earthquake-resistant design.

Describe the major engineering geological problems of the Lesser Himalaya zone with their mitigation measures.

The Lesser Himalaya lies between the MBT in the south and the MCT in the north. It is made of phyllite, slate, schist, quartzite, limestone, dolomite and some granite, and is intensely folded and faulted.

Major problems and mitigation

ProblemCauseMitigation
Landslides and slope failureWeak phyllite, schist, steep slope, heavy monsoon rain, road cuttingGentle cut slopes, retaining walls, gabions, breast walls, bio-engineering, benching
Rock fall and topplingClosely jointed hard rocks (quartzite, dolomite)Rock bolts, wire mesh, shotcrete, catch ditches
Weak rocks in foundations and tunnelsPhyllite, slate, schist have foliation and low shear strength; squeezingProper support (steel ribs, rock bolts, shotcrete); alignment across the strike of foliation
Karst / solution cavitiesLimestone, dolomiteGrouting, cut-off, avoid reservoir over limestone
Seismic activityNearness of the MBT and MCTEarthquake resistant design, avoid fault zones
Erosion and gully formationDeforested slopes, residual soilCheck dams, drainage, plantation
High sedimentWeathered soft rockDesanding, catchment treatment
Groundwater and springs dryingFractured rock, deforestationRecharge ponds, spring protection

General mitigation: detailed geological mapping, good surface and sub-surface drainage, avoiding deep cuttings, slope monitoring and early warning.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Engineering Geology II chapter 2 questions →