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针对高速公路、机场、铁路等设施上的交通荷载易引发路基土的固结沉降问题,将交通荷载视为半正弦循环荷载,分析该类荷载作用下土体的固结过程以及荷载间歇期、荷载频率、初始超静孔隙水压力等参量对固结过程的影响。通过修正Davis假定,使一维非线性固结控制方程适用于模拟具有非零初始超静孔隙水压力条件的饱和土固结过程,采用分离变量法推导半正弦循环荷载作用下一维非线性固结方程通解,并给出初始超静孔隙水压力为常数、正三角形分布和倒三角形分布3种典型初始条件下的解析解。模拟了不同的荷载间歇期、荷载频率和初始超静孔隙水压力条件下均质饱和黏土的固结过程。结果表明:固结过程中超静孔隙水压力峰值随时间增大而减小,有效应力和平均固结度峰值随时间增大而增大;初始条件的差异对固结过程的早期具有明显的影响,当初始超静孔隙水压力为0时,有效应力和平均固结度峰值均最大,其他情况下从大到小依次为倒三角形分布、正三角形分布、矩形分布;间歇期或荷载频率的差异对整个固结过程均存在影响,随着间歇期的增大,达到稳定时的平均固结峰值减小,固结过程延缓,随着荷载频率的减小,平均固结度峰值增大,固结过程加快。
Traffic load on expressways, airports, railways and other facilities tends to lead to consolidation settlement of subgrade soils. The traffic load is regarded as a semi-sinusoidal cyclic load. The consolidation process of soil under such loads, Load frequency, initial excess pore water pressure and other parameters on the consolidation process. By modifying the Davis assumption, one-dimensional nonlinear governing equations are used to simulate the consolidation process of saturated soil with non-zero initial excess pore water pressure. The discrete-variable method is used to derive the one-dimensional nonlinear solidification under the action of half-sine cyclic loading The equations are generalized and the analytic solutions are given under three typical initial conditions: initial excess pore water pressure constant, equilateral triangle distribution and inverted triangle distribution. The consolidation process of homogeneous saturated clay was simulated under different load intermission, load frequency and initial excess pore water pressure. The results show that the peak value of excess pore water pressure decreases with time, and the peak value of effective stress and average degree of consolidation increases with time. The difference of initial conditions has obvious influence on the early consolidation process , When the initial excess pore water pressure is 0, the peak value of effective stress and average degree of consolidation are the largest. In other cases, the inverted triangle distribution, the equilateral triangle distribution and the rectangular distribution are the order of magnitude; the difference between the intermittent period or the load frequency The consolidation process has an impact on the whole, as the intermittent period increases, the average consolidation peak reaches a steady decrease, the consolidation process is delayed, with the load frequency decreases, the average consolidation peak increases, solid The knot speed up.