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寒冷地区基坑悬臂桩支护工程,在桩后土体水平冻胀力作用下,易出现桩体倾斜、水平裂缝、剪断等问题.负温是水平冻胀力产生的关键因素,采用数值模拟方法,分别模拟粉质黏土、黏土在一定的负温变化下,桩体水平冻胀力的大小和分布模式,结果表明:负温越低,土体冻结速率越大,水平冻胀力越大;桩身范围内,水平冻胀力大致呈上下小、中间大的抛物线型分布,最大值出现在基坑的中下部,为开挖深度的0.5~0.8倍,力值约为冻胀前土压力的2~15倍,同时拟合出最大水平冻胀力与温度、桩顶位移之间的关系公式;此外,桩体水平位移随负温增加而增加,桩顶位置处,冻胀引起的水平位移为开挖引起位移量的0.88~11.38倍.
Under the action of the horizontal frost heave force of the soil in the cold area, the problems of inclined, horizontal cracks and shearing of the pile are easy to occur.The negative temperature is the key factor of the horizontal frost heave force.The numerical simulation The results show that the lower the negative temperature is, the larger the freezing rate of soil is and the larger the horizontal frost heaving force is. ; Within the pile body, horizontal frost heaving force is roughly up and down small, the middle of the large parabolic distribution, the maximum appears in the middle and lower part of the pit, excavation depth of 0.5 to 0.8 times the force value of frost heave before the soil Pressure of 2 to 15 times, at the same time fit the maximum level of frost heaving force and temperature, the top of the pile displacement relationship between the formula; In addition, the horizontal displacement of the pile increases with negative temperature, pile top position, frost heave caused The horizontal displacement is 0.88 ~ 11.38 times of the displacement caused by excavation.