【作者】 程强；

【导师】 周德培；

【作者基本信息】 西南交通大学 ， 岩土工程， 2008， 博士

【摘要】 本文针对红层软岩地区公路等工程建设项目中突出的开挖边坡灾害问题,结合四川、重庆、云南等省几个高等级公路建设项目,综合运用调查研究、地质力学模型试验、室内试验研究、现场试验研究及长期监测、数值模拟、经验类比等方法,深入研究了红层软岩岩体结构及岩体力学性质,并在此基础上研究了近水平地层、倾斜地层红层软岩开挖边坡灾害形成机理及防治技术,以及红层软岩风化剥蚀灾害机理及防治技术。主要研究成果有：(1)本文研究按照红层软岩地质结构特征,分类研究其致灾机理和失稳破坏模式。通过对四川、重庆、云南、甘肃等省等多条高速公路红层软岩边坡工程的广泛调研,按地质特征将其分为近水平地层、倾斜地层和断(层)—褶(曲)破碎地层三个大类以及12个亚类。根据边坡工程的特点,进一步提出了红层软岩边坡岩体结构的分类体系,划分为5个大类和11个亚类。论述了各类岩体结构特征、控制性结构面和坡体变形破坏模式。(2)采取红层软岩典型岩样,进行了抗压、抗剪和蠕变试验研究。通过室内试验和现场大剪试验,研究了红层软岩结构面抗剪强度特性。根据结构面的充填性将其分为张开少充填、闭合无充填、薄层充填和厚层充填四类。选取各类结构面进行抗剪强度试验,总结了典型结构面在剪切荷载下的变形特性,给出了典型结构面强度和变形参数参考值。(3)红层软岩结构面特别是软弱夹层的流变性显著,通过软弱夹层长期强度与短期强度试验资料分析,建议软弱夹层长期剪切强度可取短期剪切强度的75%。(4)通过原位监测、室内崩解试验和调查研究揭示了红层软岩风化崩解机理。红层软岩的风化崩解是温度和水共同作用的结果,仅温度或水环境的改变并不能引起其快速风化崩解。(5)边坡风化剥蚀的原位监测表明：气温高温差大时,泥岩边坡的风化剥蚀速率大,反之则小。中等雨强以上降雨次数对泥岩边坡的风化剥蚀量影响较大,二者呈负指数关系,小雨强降雨次数的影响不显著。泥岩在高温时的反复浸水失水情况下具有很强的风化崩解性,因此泥岩边坡的风化剥蚀主要发生在气温高降雨多的夏季。四川盆地东部某原位监测工点的数据表明,泥岩边坡5月～9月的风化剥蚀量为19.19kg/m2,占年风化剥蚀量(29.9 kg/m2)的64.2%。(6)近水平红层软岩开挖边坡灾害模式主要有滑坡、岩体拉裂变形、崩塌落石等。地质力学模型试验和数值计算分析表明,近水平红层软岩边坡滑坡灾害以软弱夹层或层面为底滑面,陡倾节理为后边界,裂隙水压力对滑移破坏有推动作用,本文结合实例给出了开挖松动区确定方法。在分析近水平红层软岩流变性对边坡稳定性影响的基础上,提出了坡体稳定性的流变力学分析的决策方法。(7)倾斜地层的红层软岩开挖边坡灾害主要是层面与节理切割岩体的滑移失稳,破坏模式取决于层面与开挖面的空间关系(详见本文第二章、第六章)。针对顺层结构红层软岩边坡的滑移—拉裂型破坏,提出了基于岩层失稳长度的开挖松动区确定方法。(8)提出了深挖路堑边坡工程系统的动态设计方法：在工前进行详细的勘察,查明边坡岩体结构特征,分析控制边坡稳定的主要结构面；对边坡稳定性进行正确的判断并进行合理的开挖和防护工程设计；施工期间进行施工监测和动态设计；在施工完成后进行系统地总结归纳。(9)通过生态防护前后的现场模拟降雨试验和坡体温度和水分的长期监测与研究,揭示了红层软岩边坡生态防护后能有效防止坡体表层风化剥落灾害的机理。红层边坡采用生态防护技术,能有效地消除表层的溅蚀和冲蚀、延迟坡面产生径流的时间、减小坡体雨水的渗透深度；同时具有减小日气温对坡体温度的影响深度、降低坡表温差(包括日温差和年温差)以及高气温时的降温和低气温时的保温等作用；还能使坡体浅层岩土含水量保持相对稳定的状态。这些优点使生态防护后的红层软岩边坡能有效防止表层风化剥落和水土流失灾害。(10)针对红层软岩开挖边坡致灾机理和破坏模式,提出了不同形式的加固防护技术,包括生态防护和工程防护有机结合的方法。提出了适用于红层软岩边坡工程的生态防护设计原则,以及基于合理坡比的生态防护技术。更多还原

【Abstract】 This article,In view of the prominent cutting slope hazards of construction projects in the area of red beds soft rock, combining a number of high-grade highway construction projects of Sichuan, Chongqing, Yunnan Province, using the methods of survey research, geology mechanical model experiment, laboratory research, field testing research and long-term monitoring, numerical simulation and experience analogy, studied the rock mass structure and mechanical properties of red beds soft rock, and on the basis of it,studied the hazards formation mechanism and the control technique of cutting slopes in approximately horizontal stratum and inclined stratum, and also the weathering and erosion mechanism, control technique of cutting slope. The main research results include:(1) The hazard mechanism and the failure mode of cutting slope in red beds soft rock are studied with classification by the geological features in this paper. Based on wide range of investigation on the red beds soft rock highway slopes in Si chuan province, Chong qing city, Yun nan province and Gan su province, according to the geological features, three main categories are divided: approximately horizontal strata, inclined strata and faults-broken folding strata, and 12 sub-categories. According to the characteristics of the slope engineering, this article further put forward the classification of rock mass structure of slopes, which is classified into 5 categories and 11 sub-categories. This article discusses the characteristics of rock mass structure, controlling structure surface and the deformation and failure mode of slopes of each kind of the structure.(2) Carried compression, shear and creep test study on the typical rock sample. Through laboratory tests and large on-site shear tests, studied the shear strength characteristics of the structure plane. According to the nature of filling of structure plane, it is divided into four categories:open and less filling, closed without filling, thin filling and thick filling. Various types of structure plane was selected to carry out the shear strength test, the characteristics of deformation of typical structure plane in the shear load has been summed up. The reference value of the strength and deformation parameters of typical structure plane has been raised.(3) The structure plane of red beds soft rock, especially the soft interlayer, is very significant in rheology. By the analysis of the long-term shear strength and the short-term shear strength experimental information, advised that long-term strength is about 75% of short-term strength.(4) By mudstone indoor weathering test, on-site monitoring and investigation, revealed the mechanism of weathering and disintegration of red beds soft rock.The weathering and disintegration of red beds soft rock is caused by temperature and water together, only the change of water environment or temperature can not causes rapid weathering and disintegration.(5) The in-site monitoring of mudstone slope weathering and denudation shows that, high-temperature and large temperature difference, the weathering rate of mudstone on slope is rapid, the contrary is small. The number of rainfall over moderate rain has a great impact on the weathering and denudation volume of the mudstone, there was a relationship of negative exponent function between the two parameters, the light rain does not affect significantly. Mudstone watered repeatedly in the high-temperature is in high nature of weathering and disintegration. Therefore the weathering and collapse of mudstone on slope usually occurres in the summer,when is in high temperatures and has more rainfall.The data of in-situ monitoring work shows that from May to September the amount of weathering and denudation is 19.19kg/m2, accounting for 64.2% of the amount of weathering all a year(29.9 kg/m2).(6)The major hazard modes of the cutting slope in approximately horizontal red beds include:landslide, ripping deformation and rock collapse, and so on. The geomechanics model test and numerical analysis shows that, the landslide is taking the weak intercalation as slip plane and the steep joint as the back boundary, water pressure in fissure has an aggravating function to the slipping destruction. The method of conforming loose zone caused by cutting is put forward. On the basis of the analysis that how the rheology of the red beds soft rock affect the stability of slope, the method of decision-making using rheological mechanics resolving the problem of the slope stability is put forward.(7)The main hazard modes of cutting slope in inclined stara are the sliding of rockmass cutting by the plane and joints, which is according to the spatial relations between the plane and the slope. In allusion to the slipping-ripping damage for bedding slope, the method of conforming loose zone caused by cutting with the terrane unstable length is put forward.(8) A dynamic design method of high way deep excavation slope is advanced, which is make engineering geology survey to find out the slope rockmass structure, analysis the main structure plane which control the stability of slope, made correct judgment of slope stability and design the slope defending engineer, then carry construction supervise and design dynamically during the construction, analysis and summarize after construction.(9)Through the on-site rainfall simulative test before and after the ecological protection, the long-term monitoring and research of the water and temperature of slope, it reveals a mechanism that the ecological protection of slopes in red beds soft rock can prevents weathering and denudation effectively. The slope of red beds adopting eco-protection technology can effectively eliminate the splash erosion and surface erosion, delay the beginning time of run-off, reduce rainwater penetration depth of the slope. And it also can reduce the impactful depth of the day temperatures, the temperature difference (including the temperature difference a day and the temperature difference a year). It also can maintain the content of shallow water of the slope at a relatively stable state. These advantages make the ecological protected slope in red beds soft rock prevent soil erosion and surface weathering effectively.(10)According to the hazard-causing mechanism and destruction modes of the cutting slope in red beds soft rock, the different forms of the reinforced and protective engineering technology, including the method of combined ecological protections with projects techniques have been put forward. The design principles of the ecological protections applying to the slope in red beds soft rock, and the eco-protection technology based on reasonable gradient of the slope have been put forward.更多还原