【作者】 吕建兵；

【导师】 傅鹤林；

【作者基本信息】 中南大学 ， 桥梁与隧道工程， 2013， 博士

【摘要】 随着公路的通车里程的迅速增长,桥头跳车成为公路中比较严重的病害之一,已备受国内外工程技术人员的关注。在桥、涵台背施工过程中有效控制台背交接处回填砂的施工工艺及回填质量,是减少由于桥头的差异沉降而引起的桥头跳车的较为重要的手段。但目前桥、涵台背填砂密实度检测国内外一直无适宜的检测方法和评价标准,因此,如何客观、有效地检测桥、涵台背回填砂的相对密实度一直都是困扰广大工程技术人员的难题。本文结合广东省交通科技项目(2008-13)”,针对基于轻便触探检测台背填砂密实度的方法展开研究,主要研究内容包括：1.根据桥、涵台背回填砂的特点,初步拟定适合于桥、涵台背回填砂密实度检测的三种方案：(1)重型动力触探法；(2)轻便触探法；(3)标准贯入法。2.建立桥、涵台背回填砂密实度检测方法选型的模糊数学评价模型,对初步拟定的三种方案进行比选,根据模糊数学理论确定桥、涵台背回填砂检测方法的最优方案。3.对优选的方案进行试验研究,用数理统计方法结合相似模拟试验的关联分析确定现场试验结果与模型试验结果之间的关系,建立台背回填砂的相对密实度D与轻便触探锤击数N。的经验关系。4.运用离散元理论,对轻便触探与砂相互作用机理进行数值模拟分析,对轻便触探过程中,回填砂粒接触、分离、碰撞与力学损伤等机理进行了分析,从理论上论证这种方法的可行性,也用静力触探试验进一步佐证可行性和实用性。5.根据荷载试验结果,对台背回填砂的沉降变化规律进行分析,得出回填砂的相对密实度的质量控制标准。6.根据室内模型试验与现场试验结果的关系,提出轻便触探检测和评定公路桥、涵台背回填砂的相对密实度的方法与标准。更多还原

【Abstract】 With the rapid development of highway construction in China, vehicle bouncing at bridge approach has become a very important influencing factor and has been paid much attention in domestic and overseas transportation study. Strict quality control in bridge-culvert back sand filling and construction process is of vital importance to prevent the differential settlement of bridge approach. However, the objective and effective test of sand relative density in bridge-culvert backfilling has been a hot yet difficult problem. In this study, based on model and on-site test under a scientific research program of the Guangdong Transportation Group—Sand Relative Density Test on Bridge-Culvert Backfilling(2008-13), the mechanism and the feasibility of light penetration test have been systematically studied. The following contents are investigated:1. Based on the abutment back sand filling, three available light penetration tests and possible program are proposed for the relative density of sand:(1) heavy dynamic penetration,(2) light penetration,(3) standard penetration.2. Fuzzy mathematic model is proposed to evaluate Light-Penetration test technique for Relative Density in Abutment Back Sand Filling, according to which three proposed scenario are compared to determine the best one.3.The optimal one is applied in model test. The relationship between model test result and on-site test result is determined by combining the mathematical statistics and the analogue simulation. Therefore, empirical relationship Dr～N10is established (N10—blow counts in light penetration, Dr—coarse sand relative density in bridge-culvert backfilling).4. Based on discrete element methods, numerical analysis is carried out to figure out the interaction between the light penetration and sand. The sand contact, separation, collision and mechanical injury are also analyzed to test the feasibility of light penetration theoretically. Static penetration test is also used to test the feasibility of light penetration with middle-sized sand, coarse sand and gravelly sand.5. According to the loading experiment result, the settlement rules are analyzed, and the quality standard of relative density for the filling sand is obtained.6. With the comparison of model test results and on-site test results, the test technique of sand relative density is obtained for the test and evaluation of bridge-culvert back-filling based on light penetration.更多还原