Moisture-Sensitive and Stress-Dependent Behavior of Unbound Pavement Materials from in Situ Falling Weight Deflectometer Tests
Moisture-Sensitive and Stress-Dependent Behavior of Unbound Pavement Materials from in Situ Falling Weight Deflectometer Tests
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原位落锤式弯沉仪测试中未粘合路面材料的湿度敏感和应力依赖性行为
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Erlingsson
中科院分区：
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作者：
Farhad Salour;S. Erlingsson
在具有地下排水系统的仪器柔性路面中，进行了实地研究，探讨了水对路面结构响应的影响。构筑物排水系统堵塞3个月；这种情况使地下水上升，使结构经受高湿度条件。重新开放的排水系统允许该结构接近其先前的排水水文状态。在监测地下水位和含水率的同时，通过多级荷载下频繁落重挠度仪试验，研究了路面结构响应。研究了非粘结层的应力敏感性和水分对其刚度的影响，并利用这些数据通过反算算法确定非粘结材料的非线性参数。排水系统堵塞后，地下水位迅速上升。地下水位的升高显著影响了路面结构的整体刚度，未粘结层的反算刚度随着含水率的增加而减小。此外，未粘结层对多级荷载表现出应力依赖性。路基在非饱和状态下表现为应力软化响应，在饱和状态下表现为应力无关行为。颗粒层表现出应力硬化行为。对通用扩展k -θ模型确定的松散非线性参数进行反算，结果表明，松散颗粒层和非饱和细粒路基材料的k1参数均随含水率的增加而减小。
In an instrumented flexible pavement with a subsurface drainage system, a field study was performed to investigate the influence of water on the response of the pavement structure. The drainage system of the structure was clogged for 3 months; this condition allowed the groundwater to rise and the structure to undergo high moisture conditions. Reopening of the drainage system permitted the structure to approach its previous draining hydrological state. Along with monitoring of subsurface groundwater level and moisture content, the structural response of the pavement was studied by conducting frequent falling weight deflectometer tests with multilevel loads. The stress sensitivity of the unbound layers and the influence of moisture on their stiffness were studied, with the intent of using the data to determine the unbound materials' nonlinear parameters through a backcalculation algorithm. The groundwater level rose rapidly after the drainage system was clogged. This rise in groundwater level significantly affected the overall stiffness of the pavement structure, and the backcalculated stiffness of the unbound layers decreased as their moisture content increased. Furthermore, the unbound layers exhibited stress-dependent behavior to multilevel loads. The subgrade showed a stress-softening response in an unsaturated condition and stress-independent behavior in a saturated state. The granular layer exhibited stress-hardening behavior. Backcalculation of the unbound nonlinear parameters determined by the universal extended k–θ model revealed that the k1 parameter decreased with increasing moisture content for both the unbound granular layer and the unsaturated fine-grained subgrade material.