| 丁金华,包承纲,陈仁朋.加筋土结构中筋材抗拉强度的取值方法研究[J].水利学报,2012,43(12): |
| 加筋土结构中筋材抗拉强度的取值方法研究 |
| A method to determine the design value of reinforcement tensile strength in reinforced soil structure |
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| DOI： |
| 中文关键词: 加筋土 设计强度 侧限约束 蠕变 模量 |
| 英文关键词: reinforced soil structure design value confined tensile strength confined creep modulus |
| 基金项目: |
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| 中文摘要: |
| 目前加筋土结构设计中筋材的抗拉强度都是根据室内标准无约束拉伸试验而得到的，不能反映筋材与土存在相互作用下的真实力学特性。采用土工格栅进行了一系列模拟加筋土实际受力状态的侧限约束拉伸试验和蠕变试验，结果表明，常规无约束条件下获得的格栅抗拉强度与实际情况相差很大，不同类型土工格栅在砂土侧限约束下的拉伸强度和延伸率变化规律与上覆荷载及拉伸速率有关，但割线模量都比无约束情况下有显著增大；侧限约束下格栅的蠕变量明显降低。因此，在加筋土结构设计中，筋材的抗拉强度指标宜采用符合工程实际受力状态的侧限约束拉伸试验强度值。另外，以无约束试验得到的筋材蠕变安全系数过于保守，侧限约束下筋材的蠕变临界应力水平有所提高。 |
| 英文摘要: |
| At present， the design tensile strength of reinforcement in reinforced soil structure is determined by indoor tensile tests in air， but such kind of unconfined tensile tests are inconformity with the real state of reinforced soil structure. A series of sand-confined tensile tests and confined-creep tests of geogrids were carried out. The testing results indicate that the real mechanical property of reinforcement in soil is quite different than those by the conventional unconfined tests. The changing rules of strength and elongation of different geogrids are related with vertical ftress and tensile rate， but the secant modulus have significant increase than the unconstrained cases. Besides， the confined-creep decreases obviously. Therefore， the sand-confined tensile strength of geogrids should be adopted as the reference value of design strength in reinforced soil structure. Moreover，the traditional factor-of-safety for creep is too conservative because confined-creep critical stress level has increased. |
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