局部加筋式路堤的载荷试验研究

Loading Test of Locally Reinforced Embankment

为了控制路堤滑移面,设计了一种在路堤中上部铺设筋材的局部加筋路堤结构。选择干砂作为填料、尼龙网作为筋材,采用自制的模型试验箱,按照25∶1相似比,以压实度K≥94%为控制指标,制备了无加筋、全断面加筋、局部3层加筋、局部4层加筋等4种路堤模型;开展了室内路堤模型静载试验;对比分析了在均布荷载P作用下,加筋路堤与无筋路堤、全断面加筋路堤与局部加筋路堤、局部3层与局部4层加筋路堤等不同工况的路堤内部土压力E、路堤沉降量s(包括路堤路面沉降量、路堤内部竖向沉降量)、路堤极限承载力Q_(uk)、坡面侧向位移L、筋材拉应变ε等参数的变化特性。结果表明:加筋能够降低路堤内部土压力、提高路堤抗侧滑性能;全断面加筋的效果最好;局部3层、4层加筋路堤的内部土压力仅分别比全断面加筋路堤的大6.15%、2.17%,限制侧向位移能力分别约为全断面加筋路堤的2/4、3/4,但筋材用量分别为全断面加筋路堤的57.14%、42.86%。

In order to control the slip surface of the embankment,a locally reinforced embankment structure in which reinforcements were laid in the middle and upper part of the embankment was designed.Selecting dry sand as the filler and nylon mesh as the reinforcement,a self-made model test box was used to prepare four kinds of embankment models such as non-reinforced,full-section reinforced,3-layer locally reinforced and 4-layer locally reinforced,which was according to the similar ratio of 25∶1 and with the degree of compaction K≥94%as the control index.The indoor static load model test was carried out.The variation characteristics of parameters such as embankment internal earth pressure E,the embankment settlement s(including the embankment pavement settlement and the vertical settlement inside the embankment),the ultimate bearing capacity Q_(uk) of the embankment,the slope lateral displacement L and the tensile strain ε of the reinforcement were compared and analyzed under the action of uniform load P,with different working conditions such as reinforced and non-reinforced embankment,full-section reinforced and locally reinforced embankment,3-layer locally reinforced and 4-layer locally reinforced embankment.The results show that:the reinforcement can reduce E and improve the anti-slip performance of the embankment;the effect of full-section reinforced embankment is the best;the internal earth pressure of 3-layer and 4-layer locally reinforced embankment is only 6.15%and 2.17%higher than that of the full-section reinforced embankment;the limited lateral displacement capacity of 3-layer and 4-layer locally reinforced embankment is about 2/4 and 3/4 of that of the full-section reinforced embankment;however,the consumption of reinforcement is 57.14%and 42.86%that of the full-section reinforced embankment.