Study On Reinforcement Technology Of Poor Foundation Of Typical Soft Soil In Qinghai Lake Area

Qinghai Lake is the largest inland saltwater lake in China,with abundant natural resources in the region,and it is of great social and economic value to protect the environmental security of Qinghai Lake area.Water grassland is the main meadow vegetation in Qinghai Lake area,which is formed due to the development of mountain slope spring water,poor surface drainage and long-term water accumulation,and water grassland belongs to the area of medium and high compressibility of poor soft soil.In recent years,with the economic development of the region,more and more projects have been built around Qinghai Lake,but these projects have to be built on water and grassland.How to effectively strengthen and treat the foundation soil of aquatic grassland and control the settlement and deformation of the foundation under the premise of ensuring that the ecological environment around the aquatic grassland is not damaged,which is a major problem that must be faced by the construction project along Qinghai Lake.Based on a highway project built along Qinghai Lake,this paper studies the reinforcement treatment method of typical poor soft soil-water grassland in Qinghai Lake area.Using indoor model test,theoretical analysis and numerical simulation,a variety of reinforcement treatment technologies that do not damage the regional ecological environment were selected,and the influence of different reinforcement schemes on the deformation of aquatic grassland and the treatment effect of each scheme were analyzed.The main research contents of this paper are as follows:1.Research on the reinforcement of water grassland by stacking precompression method.Based on the similar principle,the model test in the stacked precompression chamber was carried out,and the measured values and variation laws of the model foundation soil settlement,lateral deformation,superpore water pressure and other parameters under graded precompression load were obtained through various embedded sensors.Combined with finite element numerical simulation,the settlement deformation,lateral deformation,superporous water pressure and shear strength index of the prototype foundation soil under the stacked precompression grading load were analyzed,and the reinforcement treatment effect of the foundation soil of the water grassland reinforced by the stacking precompression method was studied.2.The reinforcement of aquatic grassland by rock-throwing and dredging was studied.Through the ultimate equilibrium theoretical analysis,indoor model test and numerical simulation,the cross-sectional morphology of rock-throwing extrusion was studied,and the deformation law of foundation soil and the empirical formula of pavement settlement under the action of rock throwing in silty soil of aquatic grassland were preliminarily estimated.The finite element numerical simulation method was used to analyze the reinforcement treatment effect of rock throwing and dredging on the foundation of aquatic grassland.3.The reinforcement of water grassland by gravel pile method was studied.The indoor model test of crushed stone pile composite foundation was carried out,and the reinforcement effect of the crushed rock pile method was verified by comparing the settlement deformation under the same load between the natural foundation and the indoor model test of the crushed stone pile composite foundation.The finite element numerical simulation method was used to analyze the deformation law and reinforcement effect of the composite foundation of crushed stone piles.4.Compare and analyze the reinforcement effects of multiple reinforcement schemes.Through the finite element numerical simulation method,the numerical calculation models of stacking precompaction method,rock throwing extrusion method,gravel pile method and strong compaction reinforcement method were established,and the deformation,superpore water pressure and cracking depth of each calculation model were compared and analyzed,and the reinforcement effect of each reinforcement scheme under the same load was evaluated,which provided a favorable reference for the research on soft soil foundation reinforcement of typical water grassland in Qinghai Lake.