平原水网地区低路堤高速公路路基动力特性研究

发布时间：2018-01-09 01:11

本文关键词：平原水网地区低路堤高速公路路基动力特性研究　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：高速公路低路堤设计具有节约土地资源、节省投资、施工方便、行车安全、景观协调、路基病害少等优点。同时降低路堤高度也有其弊端,主要有：低路堤易受地下水渗透和地表水冲刷；路堤高度降低造成交通荷载无法充分扩散传递至地基,从而加剧地基沉降变形。此外,交通动荷载振动也易引起地基不均匀沉降。这些问题可以归结为水、交通荷载对路基的作用问题。因此,如何分析交通荷载对低路堤路基的影响就是急需解决的关键技术问题。本研究以此为着眼点,重点从以下几个方面研究交通荷载作用下路基的动力响应对路基状态影响： (1)首先通过对国内外资料的调研,掌握了交通动荷载对路基的主要影响及其机理,明确研究此类影响所需的手段和方法,在此基础上提出低路堤路基研究存在的主要不足和改进方法。 (2)提出了交通荷载对低路堤影响的现场试验方法。该方法采用原位测试技术,以实际通过车辆为振源,测试内容包括路面振动、路基路面内部结构动力响应等,并重点介绍了测试元件埋设方案,方案包括测试位置的选取、适用元件的性能、埋设技术,可作为今后类似实验的参考。 (3)现场测试获取了不同车辆荷载经过路面时引起的路面各结构层、路床以及路表面的动应力、动应变、振动加速度、动位移等振动数据,分析认为,路基顶面动应力沿深度方向衰减,距路面顶面0.7m处动应力衰减达60%；公路各结构层动应力随着交通荷载的增加线性增大；路面动位移的时域波形主要由低频率组成,且主要受车辆载重影响。路面结构层动态响应随速度的增加而减小,而应力变化随着载重的增加而增加的。 (4)依据试验段现场资料建立有限元计算模型,以补充测试试验无法获取的路基动力响应状态。分析得到,当采用标准120kN幅值加载时,交通动载影响深度在2.5m范围以内比较明显,振动加速度影响范围在5.5m以内；随荷载幅值增加动应力随之增加；交通荷载相同条件下,路堤高度影响明显,随高度降低路基沉降增加明显；但路面模量的增加对沉降影响较小。
[Abstract]:Freeway low embankment design has the advantages of saving land resources, saving investment, convenient construction, traffic safety, landscape coordination, the advantages of roadbed diseases. At the same time reduce the height of embankment has its defects, are susceptible to low embankment seepage of groundwater and surface water erosion; Lu Digao degree reduces the traffic load can not fully transfer to the ground so as to spread. Increase the settlement. In addition, traffic load vibration may cause uneven settlement of foundation. These problems can be attributed to water, traffic load on the subgrade effect. Therefore, the key technical problem of how to analyze the impact of traffic load on low embankment is urgent. Based on this starting point, focuses on the influence on the roadbed dynamic response of Subgrade under traffic loads from the following aspects:
(1) first, through investigating the data at home and abroad, we have grasped the main influence and mechanism of the traffic dynamic load to the roadbed, and clearly defined the means and methods needed to study such influence. Based on that, we put forward the main shortcomings and improvement methods of the research of low embankment Subgrade.
(2) proposed field test method for effect of traffic load on low embankment. The method using in situ testing technology, to the actual vehicle through Zhenyuan, test content including pavement vibration, dynamic response of subgrade and pavement structure, and introduces the test element embedment scheme, including the selection of test scheme of position, performance, applicable elements the embedded technology, can be used as a reference for future similar experiments.
(3) field test to obtain different vehicle load caused by pavement pavement after each layer of roadbed and road surface dynamic stress, dynamic strain, vibration acceleration, dynamic displacement and vibration data analysis, subgrade dynamic stress attenuation along the depth direction, away from the pavement surface 0.7m dynamic stress the attenuation of 60%; every road structural layer dynamic stress with the traffic load increases linearly; time domain waveform of pavement dynamic displacement is mainly composed of low frequency components, which is mainly affected by vehicle load. The dynamic response of pavement structure layer decreases with the increase of speed, and the stress variation increases with load increasing.
(4) on the basis of field data of test section of the finite element model was established to test the dynamic response of Subgrade of state cannot be obtained. Results show that when using standard 120kN amplitude loading and traffic dynamic load influence depth is more obvious in the range of 2.5m, the vibration acceleration influence range within 5.5m; dynamic stress increases with the the load amplitude increased; the traffic load under the same condition, influence of embankment height obviously decrease with height of subgrade settlement increased significantly; but the pavement modulus increased on the settlement of little effect.

【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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