【作者】 武海涛；

【导师】 陈静曦；

【作者基本信息】 武汉理工大学 ， 采矿工程， 2006， 硕士

【摘要】 在膨胀土地区,无论是路堑还是路堤,及其普遍而严重的边坡变形与路床变形,都是其他土质路基中所罕见的。膨胀土地区的公路路基,由于大气物理风化作用和湿胀干缩效应,边坡土块崩解,土体抗剪强度衰减,而造成边坡的溜塌、滑坡、路基的不均匀下沉、翻浆、冒泥等变形灾害现象十分突出,而常使路基的强度和稳定性遭受破坏,造成路基失稳,影响行车安全。我国在总结膨胀土地区修建的铁路时,就有“逢堑必滑,无堤不塌”之说。 我国是世界上膨胀土分布范围最广、面积最大的国家之一。已有20多个省市、自治区发现膨胀土的分布。我国过去修建的公路一般等级较低,填挖的方量相对较小,因而膨胀土灾害问题不太突出,所以尚未引起广泛关注。然而,近年来由于高等级公路的兴建,不少地区都遇到了膨胀土带来的麻烦。许多新建公路在施工过程中就开始出现各种变形病害。膨胀土地区边坡稳定性,已成为当前公路工程中一个不可忽视的重要研究课题。 本文在膨胀土边坡已有研究成果的基础上,对降雨强度、饱和渗透系数、裂隙开裂深度以及降雨持时对膨胀土边坡稳定性影响进行参数研究,以期得到考虑与不考虑裂隙时边坡渗透场的变化规律。通过两者对比来说明在进行膨胀土边坡稳定性分析时,考虑裂隙影响的必要性。 本文在某公路膨胀土坍滑边坡进行地质成因分析的基础上,试着把影响膨胀土边坡最主要的因素(如裂隙和地质构造等)进行量化,提出了基于灰色聚类预测理论的膨胀土路堑边坡稳定性预测方法。 通过理论分析和工程实践总结得出:(1)降雨强度对膨胀土边坡的影响程度与土体本身的渗透性密切相关。(2)对于膨胀土边坡,土体渗透性愈大,对边坡的稳定性愈不利(3)裂隙的存在对土坡中孔隙水压力和体积含水量分布有着显著的影响(4)在进行考虑雨水入渗影响的膨胀土边坡稳定性分析时,必须考虑裂隙的影响。利用灰色聚类预测理论预测边坡的稳定性,具有一定的可靠性,符合膨胀土边坡破坏的特征。更多还原

【Abstract】 In the expansive soil area, whether the roadcut or the roadbank, the distortion of side slope and roadbed is very serious and usual, which seldom happens in other terrene roadbed. Highway subgrade in the expansive soil area, affected by physical weathering and wet expanding and dry pinching effect of atmosphere, the side slope soil block breaks, and the soil body shearing strength weakens, furthermore causing the side slope to slide ,collapse, landslide and the roadbed to sink asymmetrically, frost boil, frost heave and so on distortion disaster phenomenon extrusive,, making the strength and stability of roadbed distracted and making the roadbed lose stabilization, affecting the traffic safety. When our country summaries the railway constructed in the expansive soil area, it is often said that it has to slide when meeting roadcut and has to collapse when meeting bank. The side slope distortion and destruction of expansive soil roadbed has the characteristic of repeatability and long-term latent fatalness.Our country is one of the countries where the expansive soil is distributed most widely and the distribution area is the most large. The expansive soil has been found in about 20 provinces cities and Autonomous regions. The highway constructed in the past is low class in gerenal, and the filling volume or excavated volume is relatively small, so the disaster problems are not too extrusive and don’t draw too much attention. However, with the construction of high class highways, many areas meet with the trouble of expansive soil , and various distortion disasters take place in the course of construction of newly constructed highways. The stability of subgrade construction in the expansive soil has been an important research subject to be reckoned with in the present highway engineering geology.On the basis of expansive side slope research outcome, the paper makes a parameter study of the expansive soil side slope stability affected by rainfall intensity, saturation osmotic coefficient, cranny craze depth and rainfall duration, hoping to get the change law of side slope penetration field under the condition of considering or no considering the cranny. By comparing with the two conditions, the paper illustrates the necessity of considering the infection of cranny when analyzing the expansive soil side slope.On the basis of analyzing the geological cause of formation of some highwayexpansive soil collapse and slide side slope, the paper tries to quantify the most primary factors affecting the expansive soil side slope for example cranny and geologic setting and so on and put forward the expansive soil roadcut side slope stability forecasting method based on the gray clustering forecasting theory.Through theoretical analyzing and engineering practice, the paper draws the conclusion that cranny have a bigger effect on the pore space water pressure in the side slope and volume water content distribution. The lower the penetrability is, the more we pay attention to the effect of cranny. It is definitely reliable that taking advantage of gray clustering of forecasting theory to forecast the stability of side slope. It accords with the destructive characteristic of expansive side slope.更多还原