| With the successful holding of Beijing Winter Olympic Games,ice and snow sports are flourishing and the number of ski resorts is increasing year by year,thus forming many high and steep ski jump slopes.The frequent extreme weather such as heavy rainfall and freeze-thaw cycles induce slope instability and threaten the long-term stability of the project,so it is necessary to carry out research on the stability of high and steep ski jump slopes under extreme weather conditions.In this paper,the influence of rock content,rainfall intensity,freeze-thaw cycles,rainfall duration and other factors on the long-term stability of high steep ski jump slopes under extreme weather conditions is studied through a combination of centrifugal test and numerical simulation.The main research findings are as follows:(1)A series of centrifugal model tests with different stone contents were carried out to study the damage behavior and damage mechanism of ski run slopes under rainfall conditions.The study showed that the damage pattern of soil-stone mixed slope is completely different from that of soil slope.When only the variable of stone content is considered,the damage mode of soil-stone mixed slope is erosion damage,and the larger the stone content is,the less obvious the erosion effect is;the stone content is controlled at about 45 %,which increases the maximum deep displacement of the slope and the reduction of the growth multiple of fine particles at the foot of the slope by about 55.6 % and 40.33 % at most compared with other stone content.(2)The effect of stone content on slope stability under freeze-thaw conditions was studied,and the deformation law and optimal filler gradation of high and steep ski jump slope in permafrost soil were investigated.The results show that the temperature and pore water pressure of the slope soil all show the trend of fast falling-slow falling-fast rising-slow rising;the content of coarse particles has a significant effect on the change of pore water pressure;appropriately reducing the content of fine particles in the slope filler can make the temperature of the slope surface and the pore water pressure at the foot of the slope change smoothly and the vertical displacement at the top of the slope decrease.Specifically,when the content ratio of fine,medium and coarse is about 6:3:1,the gradation is better and can be used as a reference gradation for construction.(3)The effects of rainfall intensity and rainfall duration on the stability of the fill slope were studied,and the rationality of anchor support was verified.The research results show that when the rainfall intensity increases by 200 mm/d or the rainfall duration is extended by 30 days,the depth of the slope soil affected by rainfall increases to 2.5 m,the time of reaching saturation is advanced by about 1 day,the minimum safety factor is reduced to 0.652,and the time of appearance of the minimum safety factor is advanced by 1 day;before and after rainfall,the soil at the foot of the slope with small backfill depth reaches saturation 1-2 days earlier and is vulnerable to the influence of rainfall infiltration The more the anchor support is reinforced,the change of safety coefficient of critical sliding surface is reduced from 0.5334 before the support to 0.0012 after the support,and the minimum safety coefficient is improved by 58%.(4)The influence of the number of freeze-thaw cycles on the stability of slope was studied,and the rationality of anchor support was verified.The results showed that the number of freezethaw cycles increased to 3,the temperature peak of shallow soil decreased by about 50 %,the position of infiltration line increased by 0.5 m,and the safety factor decreased by about 20 %;the settlement deformation cloud after anchor rod support was obviously different from that before support,and the residual deformation after anchor rod support was 2.3 mm,which was reduced by 67.1 %,which can provide theoretical support and technical reference for future projects. |
PDF Full Text Request