广东省山区高速公路软基变形规律及沉降预测应用研究

发布时间：2018-05-15 01:28

本文选题：高速公路 + 软土地基　；参考：《东华理工大学》2017年硕士论文

【摘要】：软土在广东沿海地区或山间盆地都有广泛分布,它们的成因类型、结构和形态特征虽然不同,但都具有含水率大、压缩性高、强度低和透水性差等特点。随着高速公路延伸至山区,受地质、地形条件的限制,高填方路堤普遍存在,山间沟谷地带分布的软土直接影响高填方路堤的稳定性,地基处理十分必要。软土地基处理是一项复杂的系统工程,影响因素众多,在地基处理过程中,掌握软土的分布和工程特性、选择合适的地基处理方案并对路堤沉降进行动态监测和长期预测是研究的关键。本文以广东省山区高速公路软土地基处理关键技术为依托,采用堆载预压和塑料排水板处理方案,探讨了广东山区高速公路软土地基变形规律和沉降预测。通过现场试验和理论分析,取得如下研究成果:1.分析了广东山区软土成因类型及分布特点,对软土物理力学参数进行了数理统计分析,分析表明:含水率与孔隙比、天然密度与孔隙比、塑限与液限有较高相关性。2.依据软土分布和工程特性,选择了合适的地基处理方法,制定了软基监控方案,提出了软基监控内容、监控断面、路基稳定控制标准、卸载标准,对路基稳定判断方法特点进行了分析。3.分析了不同地基处理方案下软土地基沉降、侧向位移及沉降速率的变化规律。全路段地基沉降105-1206mm,沉降超过500mm的监测断面占41.7%,多数监测断面最大沉降速率小于20mm/d;侧向位移为6.9-234mm,平均69.2mm,侧向位移速率多数断面小于5mm/d,最大位移发生在地表以下0.5-3.5m处,地基未出现滑塌失稳现象,处理效果良好。4.依据江门-罗定高速公路软土地基沉降规律,基于指数曲线法、双曲线法及Asaoka预测方法,对公路软土地基的沉降量进行了预测,将预测结果与实测资料进行了对比分析,结果表明,双曲线法拟合相关性高,预测误差小,为本高速公路软土地基沉降预测较理想的预测方法,而Asaoka法,指数曲线法预测结果不理想,预测误差较大。公路软土路基沉降预测实现了对软基处理方案的模糊推理评判,弥补了公路软基处理方案主要依靠经验确定的不足,提高了相关决策的可靠性。
[Abstract]:Soft soil is widely distributed in Guangdong coastal areas or intermountain basins. Although their genetic types, structures and morphological characteristics are different, they all have the characteristics of high moisture content, high compressibility, low strength and poor permeability. Along with the expressway extending to the mountainous area, restricted by the geological and topographic conditions, the high fill embankment generally exists, and the soft soil distributed in the gully and valley zone between the mountains directly affects the stability of the high fill embankment, so the foundation treatment is very necessary. Soft soil foundation treatment is a complex system engineering, and there are many influencing factors. In the process of foundation treatment, the distribution and engineering characteristics of soft soil are grasped. The key to the study is to select suitable foundation treatment scheme and to dynamically monitor and forecast embankment settlement. Based on the key technology of soft soil foundation treatment of highway in mountainous area of Guangdong province, the deformation law and settlement prediction of soft soil foundation of Guangdong mountain expressway are discussed by adopting the scheme of surcharge preloading and plastic drainage board treatment. Through field test and theoretical analysis, the following research results are obtained: 1. 1. The genetic types and distribution characteristics of soft soil in Guangdong mountainous area are analyzed. The physical and mechanical parameters of soft soil are analyzed by mathematical statistics. The results show that water content and porosity ratio, natural density and porosity ratio, plastic limit and liquid limit have a high correlation. According to the distribution of soft soil and engineering characteristics, the suitable foundation treatment method is selected, and the monitoring scheme of soft foundation is established. The contents of soft foundation monitoring, monitoring section, roadbed stability control standard and unloading standard are put forward. The characteristics of the method for judging subgrade stability are analyzed. The variation rules of settlement, lateral displacement and settlement rate of soft soil foundation under different treatment schemes are analyzed. The subgrade settlement of the whole section is 105-1206mm, the monitoring section with settlement exceeding 500mm accounts for 41.7mm, the maximum settlement rate of most monitoring sections is less than 20mm / d, the lateral displacement is 6.9-234mm, the average is 69.2 mm, and the lateral displacement rate is mostly less than 5mm / d, the maximum displacement occurs at 0.5-3.5m below the ground surface. There is no collapse and instability phenomenon in the foundation, and the treatment effect is good. 4. According to the settlement law of soft soil foundation of Jiangmen-Luoding Expressway, based on exponential curve method, hyperbolic method and Asaoka method, the settlement of soft soil foundation of highway is forecasted, and the result is compared with the measured data. The results show that the hyperbolic method is an ideal method for predicting the settlement of soft soil foundation in this expressway, but the prediction results of Asaoka method and exponential curve method are not ideal and the prediction error is large. The prediction of roadbed settlement of highway soft soil realizes the fuzzy reasoning judgment of soft foundation treatment scheme, which makes up the deficiency that highway soft foundation treatment scheme mainly depends on experience, and improves the reliability of relevant decision.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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