Research Of The Natural Infiltration Reduction Of Glacier Lake Moraines Clogging In The Himalayas

Based on former people’s research on the permeable silt characteristics of plateau mountain gully fluvial sediment, and also according to research on the investigate data of dozens of major glacial lake in the research project of the fatal geological hazards investigation and mitigation in the Himalayas Range Area, this thesis has made a conclusion that there should also have infiltration clogging effect existed in the hydrostatic deposition–infiltration process of the glacial lake which has been formed in the glacier retreat (stage). In its advance stage, the glacier’s enormous traction to the ice–water’s mixed sediments can make the early moraine ridge pressed more solid. And this maybe the reason for the increase of density and the decrease of the permeability coefficient of the moraine ridge soil.With the help of the National Natural Foundation Project–clogging effect onplateau reservoir dam foundation loose medium permeability effect and mechanism, alarge-scale indoor infiltration clogging experiment instrument has been completed.This instrument includes four parts: clogging-passing experiment container, porewater pressure monitoring device, clogging material feeding device and thecirculating flow water pressure device.According to the study of the plateau glacial deposits–moraines’ particlecharacteristics, most of the materials cannot have the friction effect and still show theweathering morphology, in addition to a small number of coarse clast’s local friction.Therefore granite slope sediments have been gathered from the ChangchunXinlicheng Reservoir Area as the indoor infiltration clogging test material, and amineral composition comparison with moraines has been made. There is no mica inthe mineral composition of the sample, and most of the particle is angular orsubangular. Moraine ridge soil structure is mostly crude shape structure, and mainly in coarse particles, with a deficiency of the middle particles. And except using thegranite slope sediments as the test materials, the fine particles have been used as thetest additional materials which have been chosen from five intervals in order to makethis large-scale indoor infiltration clogging experiment completed.Various infiltration clogging models have been analyzed and established, mainlydivided into five kinds: surface clogging model, internal clogging model, surface-internal double clogging model, no clogging model and the assumption cloggingmodel, and the surface clogging model is a two-dimensional model, internal cloggingmodel and surface-internal double clogging model is a three-dimensional model.Also accoding to the data analysis in this experiment, it can be found that thepermeability coefficient decreases because there is clogging occurred in the inner ofthe gradation soil. The surface-internal double clogging will occur in the soil whenthe inputted clogging sample’s particle size is between0.125~0.25mm.The glacier is not a stable ice body, but moves continuously in the forward andbackward alternately. According to analysis of the traction in the glacial advance stageand the hydrostatic deposition in the glacier retreat stage, the moraines infiltrationreduction model is established and the glacier moraine’s natural infiltration reductionmechanism has been exploratory explained.