废旧轮胎片体填充加筋桥台的协同工作机理与稳定性分析方法研究

Black pollution caused by waste scrap tire becomes more and more serious and threatens people's survival environment. Tire-Derived Aggregates (TDA) are used as backfill in geotechnique to recycle waste material. However, the design theory of reinforced TDA bridge abutment is imperfect. Therefore, this project studies the critical scientific issues such as the synergistic work mechanism for reinforced TDA bridge abutment. By laboratory tests, the variation of engineering properties of TDA-soil composites with TDA size and shape, compaction density, mixing quantity and varieties of soil are studied. Through tests and discrete element method, the synergistic work mechanism of reinforcement-TDA-soil composites is studied, and the deformation, stress transmission mechanism and interface failure mode of TDA-soil composites are revealed under the static load and vehicle dynamic load. Rheological properties of TDA-soil composites are discussed and a rheological model is proposed. The model tests are performed to study the time-space effect of bridge abutment stress, deformation and displacement, the gradual evolution process of internal crack surface and the distribution of soil pressure on facing. With the effects of vehicle dynamic load and the rheological properties of reinforced TDA backfill, the stability analysis method of reinforced TDA bridge abutment is put forward, and the design theory system of reinforced TDA bridge abutment is constructed.

废旧轮胎形成的黑色污染严重威胁着人们的生存环境，将轮胎片体TDA（Tire-Derived Aggregates）用于桥台等土木工程中可以起到变废为宝的目的。但目前加筋TDA桥台的设计理论还很不完善，为此本项目将对加筋TDA桥台协同工作机理等关键科学问题进行研究。通过室内试验，研究TDA-土复合填料的类土力学性能指标随TDA尺寸和形状、压实密度及土掺量和种类等的变化规律。通过试验和离散元方法研究筋材-TDA-土协同作用机理；揭示在静荷载和车辆动荷载作用下TDA-土复合体的变形规律、应力传递机制及界面失效模式。研究TDA-土复合体的流变特性，并提出流变模型；通过模型试验研究桥台应力、变形和位移等的时空效应，填料内部破裂面的渐进演化过程，以及墙面上土压力的分布规律。提出考虑车辆荷载动力效应和加筋TDA填料流变效应的加筋TDA桥台的稳定性分析方法，建立加筋TDA桥台的设计理论体系。

废旧轮胎形成的黑色污染严重威胁着人们的生存环境，将轮胎片体TDA（Tire-Derived Aggregates）用于桥台等土木工程中可以起到变废为宝的目的。但目前加筋TDA桥台的设计理论还很不完善。为此本项目对加筋TDA桥台协同工作机理等关键科学问题进行了研究。项目采用不同质量比的废旧轮胎片体（TDA）掺入风化料，制备不同含水率的混合料，通过试验系统研究了TDA混合料的压实特性、压缩变形和渗透性规律；研发了适用于TDA混合料研究的新型大尺寸变水头渗透仪、大型拉拔仪、大型直剪仪、桥台模型试验箱和大型破坏性模型试验系统（3.5m×3.5m×3m）；通过大型直剪试验，揭示了大尺寸TDA与TDA、砂、混凝土、土工格栅、土工布等的剪切机理；通过大型拉拔试验，利用自主研制的传感型土工合成材料SEG研究了橡胶颗粒对筋土界面特性的影响，揭示了筋材的应力传递机制，建立了反映筋土界面非线性作用的双曲线本构模型，发现橡胶颗粒含量对筋土界面的摩擦特性有较大影响，且存在最优值；开展了SEG加筋TDA桥台性能模型试验，揭示了TDA质量比与条形荷载位置对土体模型的极限承载力、侧向变形和基础沉降的影响，揭示了桥台应力、变形和位移等的时空效应，以及填料内部破裂面的渐进演化过程；通过分析土体中SEG筋的应变值，表明加筋TDA桥台滑裂面形状与条形基础位置和TDA含量有关。本项目不仅为加筋TDA桥台设计提供了理论基础，而且为我国推广TDA在土木工程中的应用提供了技术支持。