香溪河段公路岸坡再造机理试验与应用研究

发布时间：2018-05-05 03:17

  本文选题：香溪河 + 公路岸坡再造　； 参考：《中国地质大学》2015年博士论文

【摘要】：三峡水库已经历多个蓄水阶段,于2010年10月首次蓄水至175m水位。2013年开始正常运营后,库水位每年在145m至175m之间周期性升降,水位变幅带(消落带)范围高达30m。宜巴高速公路主线局部段和兴山连接线(以下简称“研究区”)是沿香溪河库岸设计和建设的通往兴山县和神龙架林区的旅游干线公路。香溪河库岸段公路路面设计高程在176m～200m之间,离175m正常蓄水位很近,公路岸坡和桥基边坡长期处于水位循环涨落(饱水-风干)的环境中。高达30m的水位变幅,加上蓄水、泄洪而频繁发生的水位升降甚至联合强降雨作用所构成的复杂动水条件,必将成为新一轮岸坡再造的重要营力,也将使得三峡库区岸坡的水文、地质环境条件发生重大改变,势必引发新的岸坡再造和库岸滑坡灾害等,严重威胁到了库区的交通安全和库区人民的生命财产安全。因此,对库岸公路涉水岸坡进行再造机理研究,具有重要的理论和现实意义。本文在现场调查分析的基础上,通过现场钻孔取样、现场岩体声波测试、室内岩块物理力学性质试验、离心模型试验、数值模拟分析与现场监测分析等手段,对研究区岸坡岩体质量的劣化机制、土质滑坡的塌岸机理、岸坡岩体质量分级以及研究区岸坡再造类型及其稳定性进行了分析研究,取得了以下主要成果：(1)研究区岸坡工程地质特征研究与岸坡再造类型分类①通过对研究区的综合调查与分析,将研究区岸坡结构类型及其特征进行分段描述,并将岸坡再造类型总结为冲刷磨蚀型、坍崩滑塌型和整体滑移型三大类。②通过对研究区典型岩土体进行物理力学性质试验,获得了研究区岸坡岩土的物理力学参数,为离心模型试验和数值模拟计算提供了参数依据。(2)岸坡岩体(石)劣化机制试验研究成果①通过对典型岩质岸坡进行试验研究,试验成果表明受库水位升降影响粉砂岩岸坡和灰岩岸坡的岩体裂隙较发育,为较破碎～破碎岩体。②通过对岩石干湿循环试验试样进行单轴抗压强度劣化试验,成果表明粉砂岩和灰岩强度劣化程度随干湿循环次数增加呈增长发展趋势；相同条件下,粉砂岩的劣化速率明显高于灰岩,说明库水对软岩的影响作用更加明显。③通过耐崩解性试验,成果表明岩石的耐崩解性指数(Id)随崩解循环次数(N)的增加而减小,且两者存在对数函数关系,即Id=a×Ln(N)+b,式中a和b为与岩性有关的系数。针对粉砂岩,还发现系数a和b还与试样取自的高程有关,高程越高的岩块越容易风化崩解,同时a和b表现为降低。(3)库水升降作用下岸坡岩体质量分级研究成果①针对现有方法的不足,考虑到三峡库区周期性升降的规律性,引入了岸坡“岩体质量总劣化度”Dh(n)和“岩体质量年度劣化度”d (h)两个指标,对涉水岸坡岩体进行岩体质量分级评价,建立了岸坡岩体质量分级评价预测公式：[BQ]h(n)=(1-nd(h))[BQ]h(o)。②依据BQ法对库区两个典型岸坡进行了岩体质量分级应用与评价,并对粉砂岩L岸坡不同高程段岩体质量进行预测,提出了岩体质量预测公式,即：上述公式表明岸坡岩体质量[BQ]与高程h和水库运行年数n有关。(4)公路库岸塌岸机理离心模型试验研究成果采用离心模型试验,研究了水位骤降和降雨耦合水位骤降两种工况下库岸滑坡“启动-发展-破坏”过程的塌岸机理。模型试验成果表明：水位骤降是导致公路库岸滑坡的最主要影响因素之一。水位骤降发生的瞬间,岸坡沿深部软弱面产生了整体滑动,随后滑动位移逐级增大；同时,位于原水位线附件的岸坡立刻产生细小裂纹,而原水位线以下坡面上的裂纹随后逐级出现并向两端扩展延伸,受前部滑塌牵引影响后部裂缝也逐渐扩大。孔压监测值的突变分析表明,裂纹逐级还存在向边坡内部延伸。降雨过程降低了边坡土层的抗剪强度,使边坡产生了少量的位移,但未影响边坡的整体稳定性。试验研究表明,两组工况下涉水岸坡均发生了整体性滑动,并且滑动面均沿着深部的软弱层发生发展。(5)研究区岸坡稳定性分析成果①研究区典型滑坡在不同降水条件下的稳定性特征,分析认为：妃台山滑坡模拟研究成果表明,在库水以0.6m/d和1.2m/d下降2种工况下,滑坡稳定系数都大于1,表明目前滑坡体是稳定的。但库水位下降速度对滑坡的稳定性影响明显,下降速度越快,滑坡越不稳定。周家坡滑坡模拟研究成果表明,在库水以及2.0m/d三种模式下降时,滑0.6m/d、1.2m/d坡稳定系数均有明显下降,稳定系数的降低速率和幅度和库水位下降速率关系密切,库水位骤降对库岸滑坡的稳定性极为不利,库水位快速下降(骤降)是库岸潜在滑坡体和古(老)滑坡复活的主要诱因之一。同时,在库水位下降到145m后稳定的一段时间内,三种模式下的滑坡稳定系数达到最低后均有少量的提高(反弹)。②基于对公路建设中典型边(滑)坡体的深部变形监测成果的分析评价,认为堆积体滑坡的变形发生发展主要是受工程施工联合降雨尤其是较强降雨综合作用影响的结果。公路建设过程中挖方、堆载、施工放炮、机械车辆的频繁碾压改变了坡体外形,打破了坡体的初始应力平衡状态,而降雨及地表水入渗弱化了坡体物质的抗剪强度,增加了坡体的重量,加速了边坡变形,从而导致滑坡的产生,这也是工程滑坡多发生在雨季的原因。③综合上述研究成果,充分考虑岸坡基本因素和影响因素联合作用影响,采用动态权重模糊评价体系,对研究区岸坡稳定性进行了定性分类评价,将研究区公路岸坡稳定性划分为稳定、基本稳定、次不稳定和不稳定四大类。
[Abstract]:The Three Gorges reservoir has experienced a number of water storage stages. After the first storage of water to 175m water level in October 2010, the reservoir water level fluctuated periodically from 145m to 175m each year. The range of the water level variation zone (the falling zone) was higher than that of the local section of the main line of the 30m. yicba highway and the Xingshan connection line (hereinafter referred to as the "study area") along the Xiangxi River. The design and construction of the bank bank to the Xingshan county and the Shenlong stand of the tourist trunk road. The highway pavement design elevation of the Xiangxi River bank section is between 176m and 200m, which is close to the normal storage space of the 175m. The highway bank slope and the bridge foundation slope are in the environment of the water level circulation fluctuation (full water air drying) for a long time. The level of the water level of up to 30m, plus the water storage, is added to the water. The frequent water level of flood and even the complex dynamic water conditions formed by combined heavy rainfall will certainly become an important force for a new round of bank slope reengineering. It will also make a great change in the hydrology and geological conditions of the bank slope in the Three Gorges Reservoir area, which will inevitably lead to the new bank slope reengineering and the landslide disaster of the bank bank, which seriously threatens the reservoir area. Traffic safety and the life and property of the people in the reservoir area are safe. Therefore, it is of great theoretical and practical significance to study the reengineering mechanism of the bank slope of the bank highway. On the basis of the field investigation and analysis, this paper through the field drilling sampling, the field rock sound wave test, the indoor rock mass physical and mechanical properties test, the centrifugal model test, the numerical value. By means of simulation analysis and field monitoring and analysis, the deterioration mechanism of rock mass quality in the bank slope, the mechanism of landslides, the quality classification of slope rock mass and the type and stability of the bank slope reengineering in the study area are analyzed and studied. The following main achievements have been obtained: (1) the research on the engineering geological characteristics of the bank slope and the reengineering of the bank slope in the study area Type classification (1) by comprehensive investigation and analysis of the study area, the type and characteristics of the bank slope structure in the study area are segmented, and the types of bank slope reengineering are summarized into three categories: erosion and erosion type, collapse type and holistic slip type. The physical and mechanical parameters of the slope rock provide parameter basis for the centrifugal model test and numerical simulation. (2) the experimental research results of the deterioration mechanism of the rock mass (stone) of the bank slope are tested by the experimental study on the typical rock slope. The results show that the reservoir water level rise and fall affect the rock fracture of the silt slope and the limestone bank slope. The results show that the deterioration degree of the strength of the siltstone and limestone increases with the increase of dry and wet cycle times, and the deterioration rate of the siltstone is higher than that of the limestone under the same condition, indicating that the influence of the reservoir water to the soft rock is more important. Through the disintegration test, the results show that the rock collapse resistance index (Id) decreases with the increase of the number of disintegration cycles (N), and there is a logarithmic function relationship between them, that is, Id=a * Ln (N) +b, a and B are related to lithology in the form of the siltstone, and the coefficient a and B are also related to the elevation of the sample, and the higher the elevation The rock mass is easier to be weathered and disintegrate, and the performance of a and B is reduced. (3) study on the quality classification of rock mass in the bank slope under the action of reservoir water fluctuation (1), in view of the shortcomings of the existing methods, considering the regularity of the periodic rise and fall of the Three Gorges Reservoir area, two indexes of the "total degradation degree of rock mass" Dh (n) and the "annual deterioration degree of rock mass" (d (H)) are introduced. According to the evaluation of rock mass quality classification, the prediction formula of rock mass quality classification is established: [BQ]h (n) = (1-nd (H)) [BQ]h (o). (2) the rock mass quality classification of two typical bank slopes in the reservoir area is applied and evaluated according to BQ method, and the rock mass quality of the siltstone L bank slope at different elevation is predicted, and the rock constitution is put forward. The formula of quantity prediction, that is, the above formula shows that the mass [BQ] of the bank slope is related to the height of the elevation h and the year number of the operation of the reservoir. (4) the centrifugal model test of the bank bank collapse mechanism of the bank bank is carried out by centrifugal model test, and the bank bank landslide "start development failure" of the bank slope under the water level drop and the sudden drop of the rainfall coupling water level are studied. The result of the model test shows that the sudden drop of water level is one of the most important factors that lead to the landslide of the highway bank. At the moment of the sudden drop of the water level, the bank slope has a whole sliding along the deep soft surface, and then the sliding displacement increases step by step. At the same time, the bank slope at the original water level line appendix produces small cracks, and the original water level is below the water level line. The cracks on the sloping surface then appear step by step and extend to the two ends, and the cracks in the rear part are gradually expanded by the sliding traction of the front part. The abrupt analysis of the monitoring value of the pore pressure indicates that the crack is also extended to the side of the slope. The rainfall process reduces the shear strength of the slope soil and causes the slope to produce a small amount of displacement, but does not affect the slope. The experimental study shows that the slope of the water wading slope in the two groups is all sliding, and the sliding surface is developed along the deep weak layer. (5) the stability analysis of the bank slope in the study area (1) the characteristics of the stability of the typical landslides in the study area under different precipitation conditions, the analysis is that the simulation of the imperial concubine Taishan landslide The results show that the landslide stability coefficient is more than 1 under the 2 conditions of 0.6m/d and 1.2m/d decline, which indicates that the landslide body is stable at present. But the decline velocity of the reservoir water level has an obvious effect on the stability of the landslide, the faster the decline speed is, the more unstable the landslide is, the results of the Zhou Jiapo landslide simulation study show that when the three modes of reservoir water and 2.0m/d fall, The slope stability coefficient of sliding 0.6m/d, 1.2m/d slope stability coefficient decreased obviously, the decrease rate and amplitude of stability coefficient are closely related to the decline rate of reservoir water level. The sudden drop of reservoir water level is extremely unfavorable to the stability of bank slope, and the rapid decline of reservoir water level (sudden drop) is one of the main causes of the resurrection of potential landslides and old landslides in the bank bank. In a stable period after falling to 145m, the landslide stability coefficient in the three modes reached a minimum and a little increase (rebound). Secondly, based on the analysis and evaluation of the monitoring results of the deep deformation of the typical side (slippery) slope in the highway construction, the development and development of the landslide is mainly due to the joint rainfall of the construction and especially the comparison. The result of the influence of the comprehensive effect of heavy rainfall. In the course of highway construction, excavating, loading, construction and blasting, the frequent rolling of mechanical vehicles changed the shape of the slope body, broken the initial stress balance state of the slope, and the rainfall and surface water infiltration weakened the shear strength of the slope body material, increased the weight of the slope body, accelerated the slope deformation, thus guided the slope deformation. Thus, the slope deformation was accelerated, thus guiding the slope deformation and thus guiding the slope. This is also the cause of the landslide, which is also the cause of the landslide occurring in the rainy season. 3. Comprehensive analysis of the above results, fully considering the impact of the basic factors and factors of the impact of the bank slope, using the dynamic weight fuzzy evaluation system, the stability of the bank slope in the study area is qualitatively classified and evaluated, and the stability of the bank slope in the study area is divided into stability. Fixed, basically stable, sub unstable and unstable four main categories.

【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U416.1;TV223
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本文编号：1845947