交通荷载作用下轮胎—格栅加筋土挡墙力学性能研究

发布时间：2018-04-21 01:27

本文选题：废旧轮胎 + 交通荷载　；参考：《湖北工业大学》2017年硕士论文

【摘要】：随着我国经济发展的深入,国内高速公路建设的基本完善,物流行业的大力发展,运输车辆也逐年增多。近年来各地超长超重车辆大量出现,给道路工程带来了严重危害。因此,针对加筋土挡墙在交通荷载作用下的动力特性的研究深受重视。同时,车辆数量的增加,将面临更多有关废旧轮胎的处理问题。废旧轮胎抗拉强度高、抗磨损、抗老化、韧性高、防震性能优良,轮胎加筋施工快速简单,成本低廉,具有良好的变形适应性能和长期稳定性。近年来,越来越多的废旧轮胎作为加筋材料,被应用到加筋挡土墙中。本文将废旧轮胎与双向格栅组合形成共同加筋体,作用在加筋土挡墙中,通过室内模型试验,将对轮胎-格栅加筋土挡墙在交通荷载下力学性能展开深入研究。本文通过自主研发的交通循环荷载施加装置对试验中交通荷载进行模拟,对轮胎-双向格栅加筋土挡墙开展了室内模型试验。将双向格栅、轮胎、土工格室与轮胎-格栅组合筋材进行加筋对比分析,通过对相同车速、不同车辆载荷的情况进行模拟,分析不同加筋土挡墙的加速度、动土压力、墙面变形,研究其在交通荷载作用下的动力学特性和墙面变形的规律。试验结果表明:轮胎-格栅加筋材料相比土工格室、轮胎和土工格栅单一加筋,更有利于提高挡土墙的抗震性能和稳定性,减少墙面变形。在轮胎-格栅组合加筋方案中,轮胎布置间距相隔轮胎半径大小的方案效果较优,且可节约30%的材料成本。因此,根据最优轮胎-格栅组合方案,分析了在不同车速条件下挡墙的动态响应特性和规律。在交通荷载作用下,轮胎-格栅加筋土挡墙面板变形和加速度大小随相对墙高增大而增大,最大变形位于相对墙高y/H=0.7处,加速度在墙顶达到峰值。动土压力随荷载幅值改变发生相应变化,在达到峰值后,增加速率变缓并趋于稳定。通过函数拟合,加速度放大系数随相对墙高的增大呈指数函数放大,同时随着相对荷载幅值的增大呈对数函数增加。最后,本文通过动、静试验对比,对轮胎-格栅加筋土挡墙墙顶累积沉降与土压力进行对比分析。在相同幅值大小的静载与循环荷载下,两次循环加载后的累积沉降逐渐超过静载作用下的累积沉降;四次循环加载后的动土压力峰值逐渐超过静载作用下土压力峰值。稳定后60km/h的交通荷载下土压力峰值超出同等静载幅值下土压力峰值20%。因此,挡墙累积沉降与动土压力受循环加载次数与加载时长的共同作用而变化。
[Abstract]:With the development of economy, the improvement of highway construction and the development of logistics industry, the number of transport vehicles is increasing year by year. In recent years, a large number of super-long and overweight vehicles appear in various places, which brings serious harm to road engineering. Therefore, the study of the dynamic characteristics of reinforced earth retaining wall under traffic load is paid more attention. At the same time, the increase in the number of vehicles, will face more problems with the disposal of used tyres. Waste tires have high tensile strength, wear resistance, aging resistance, high toughness, excellent seismic resistance, rapid and simple construction of tire reinforcement, low cost, good deformation adaptability and long-term stability. In recent years, more and more used tires as reinforced materials are used in reinforced retaining walls. In this paper, the waste tire and bidirectional grille are combined to form a reinforced body, which acts on the reinforced earth retaining wall. Through the indoor model test, the mechanical properties of the tire and grille reinforced earth retaining wall under traffic load are studied in depth. In this paper, the traffic load is simulated by the self-developed traffic cyclic loading device, and the indoor model test is carried out for the tire and bidirectional grille reinforced earth retaining wall. By comparing and analyzing the reinforcement of two-way grille, tire, geogrid and tire grille composite reinforcement, the acceleration and dynamic earth pressure of different reinforced earth retaining wall are analyzed by simulating the situation of the same speed and different vehicle loads. The dynamic characteristics of wall deformation under traffic load and the law of wall deformation are studied. The experimental results show that compared with geogrid reinforced material, single reinforcement of tire and geogrid can improve the seismic performance and stability of retaining wall and reduce the deformation of wall. In the combination reinforcement scheme of tire and grille, the effect of tire layout spacing separated by tire radius is better, and the material cost can be saved by 30%. Therefore, according to the optimal tire-grille combination scheme, the dynamic response characteristics and laws of the retaining wall under different speed conditions are analyzed. Under the action of traffic load, the deformation and acceleration increase with the increase of the relative wall height. The maximum deformation is located at the relative wall height y/H=0.7, and the acceleration reaches the peak at the top of the wall. The dynamic earth pressure changes with the change of load amplitude. After reaching the peak value, the increasing rate slows down and tends to be stable. Through the function fitting, the acceleration magnification coefficient increases exponentially with the increase of the relative wall height and the logarithmic function with the increase of the relative load amplitude. Finally, through dynamic and static test, the cumulative settlement and earth pressure on the top of reinforced earth retaining wall with tire and grille are compared and analyzed. Under the same amplitude of static load and cyclic load, the cumulative settlement after twice cyclic loading gradually exceeds the accumulated settlement under static load, and the peak value of dynamic earth pressure after four cyclic loading gradually exceeds the peak value of soil pressure under static load. The peak value of earth pressure under traffic load of 60km/h after stabilization is higher than that under the same static load amplitude of 20. Therefore, the cumulative settlement and the dynamic earth pressure of the retaining wall are influenced by the cyclic loading times and the loading time.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U417.11

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