| Papers in yunnan li xiang railway are YuanBaoShan tunnel entrance section as the research background, to carry out the deposit of the mouth of the cave and mechanical characteristics, the shear strength of different degree of compaction test and the field monitoring measurement and the analysis of slope stability, etc.Test results are different from general soil, its particle size distribution of the distribution is discrete, particle gradation is not continued and the presence of size larger stone structure, particle size are mainly concentrated in the range of 0.075 mm to 5 mm, less than 0.075 mm of the content of the soil particles is less.Loose deposit of shear strength increased with the increase of the vertical stress increases, its physical and mechanical parameters are increased with the increase of the vertical stress.Phase when the vertical stress at the same time, the shearing strength of the loose deposit and the sample closely related to the degree of compaction, and with the increase of degree of compaction shear strength increased dramatically.Loose deposit area in the process of the excavation of tunnel under the influence of gravity, and due to the poor bonding are itself, there will be a tunnel boundary of upward slope instability phenomenon, main buckling mode: tension failure and shear failure, local subsidence damage and pile collapse destroyed.Research are the physical properties and the mechanical properties of the deposit and combined with loose and side slope instability mechanism, think deposit area of tunnel excavation should excavation and supporting, to improve its safety coefficient, and the deposit for slope treatment can improve the compaction and shear strength and mechanical parameters,and thus enhanced the safety coefficient of stability of slope, according to indoor direct shear test conclusion analysis found that the higher the degree of compaction,the safety of the slope stability coefficient is higher, considering the actual operating limits, suggested that choose the degree of compaction of 0.9.In practical engineering are regional tunnel excavation scope of slope due to its geological conditions, the influence of side slope deformation, obvious sliding, appeara large number of cracks, holes in the construction and support.Loose deposit area of tunnel portal after reinforcement, through theoretical calculation and monitoring analysis, can temporarily in limit equilibrium state, but considering the influence to the stability of slope is the rainy season, may destroy limit equilibrium state and to slope and slope reinforcement.According to experimental data, this paper on the slope toe deposit of loose and backfill compaction process, and on the back slope did spray anchor net, through the theoretical calculation of slope stability safety factor meet the specification requirements, the monitoring found that the hole and the slope is in steady state.Visible compaction of the loose deposit has a great influence on shear strength and mechanical parameters, the larger the degree of compaction of the actual project in slope stability has obvious reinforcement effect. |
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