高寒山区散粒体斜坡形成演化过程及灾变机理研究

发布时间：2018-04-30 09:39

本文选题：散粒体斜坡 + 形成演化过程　；参考：《成都理工大学》2016年博士论文

【摘要】：散粒体斜坡主要以同量级、近均匀的岩石颗粒形成的集合体所堆积的坡体,其物质组成具有结构松散、高压缩、强透水、低粘结力等独特的物理力学特征。其自稳性差、复发性强、突发性高的成灾特点,对高寒山区公路、铁路等基础设施的建设、安全运营有着非常重要的影响,甚至在局部地段起到至关重要的制约作用。散粒体斜坡主要分布于高寒峡谷地带及易发高烈度地震活动区,其分布范围广阔、复发频率高、连锁反应多样,特别是易于转化成一系列灾害链的效应,从而可长期危害人类的工程活动,同时,它还为我国建立绿色通道理念带来了不少的生态环保问题。可见,随着基础设施建设的大规模推进,研究作为高寒山区地质灾害之一的散粒体斜坡演化及灾变问题,不仅为山区公路等工程设施的防灾治理提出实践指导,也丰富了地质灾害理论研究。本文选取了天山公路、中巴公路作为高寒山区散粒体斜坡研究案例,以现场调查勘察及地质环境资料收集、文献检索等工作为基础,查明了天山公路、中巴公路散粒体斜坡分布规律及结构特征,基于高寒山区冻融循环、冰劈作用等特殊外动力效应,采用室内试验,研究了循环冻融及冰劈作用对散粒体形成的微观改造、宏观裂化机制,利用现场定点重复三维激光扫描,实测并计算了裸露基岩产屑率;综合分析了散粒体失稳的诱发因素,采取物理模拟及数值模拟,验证了散粒体斜坡在降雨融雪、滚石冲击作用下的启动失稳模式、灾变机理及其堆积特征,分析了其散粒体链式反应的灾害链效应,总结了泥石流典型特征参数计算公式。综上所述,本文针对以天山公路、中巴公路所代表的高寒山区散粒体斜坡的研究,较为系统地讨论了散粒体斜坡的演化过程、灾变效应,对该类特殊形式的斜坡工程治理提供了基本的灾变模式及典型设计参数。取得主要研究成果如下:(1)从天山公路、中巴公路散粒体斜坡的分布地质背景出发,对公路沿线散粒体斜坡进行详尽的调查,获取了空间展布规律和线密度特征;并根据散粒体斜坡特征结合资料查阅对其进行重新分类,增加了无粘粒散粒体和含粘粒散粒体两类斜坡,揭示了无粘粒散粒体斜坡的如下典型特征:颗粒粒度差别较大,重力分选性明显,颗粒组成以碎石、角砾为主,次为粗砂、中砂,几乎不含粘粒,松散无粘聚力等性质;含粘粒散粒体斜坡崩积层存在“二元结构”,坡面堆积层结构由表砾层与底粒层两层组成,上层表砾层由岩砾组成无粘聚力,底层有一定粘聚力。无粘粒散粒体斜坡形成过程可归纳为高位剥离、堆积运移、溜动;而含粘粒散粒体斜坡形成可归纳为高位剥离、堆积运移、岩块冻融分解、淋溶固结、蠕滑等一系列过程。(2)通过对冻融循环条件下岩石微裂隙扩展进行详细而深入的研究,得到了三种工况(天然、常温饱水、高温饱水)三类岩石(花岗岩、千枚岩、砂岩)其早期强度迅速提高、后期强度逐渐降低的规律,冻融前期岩石内部少量矿物组分迁移矿物进入并封闭了部分微裂隙空间来提高岩石的强度,冻融后期岩石闭合的微裂隙在多次循环后微裂隙局部贯通,降低后期强度。(3)基于高寒山区岩体结构面劣化特征,采取岩块自制裂缝的冰劈试验,揭示岩体形变可归纳为冻缩、冻胀及融缩三阶段过程。发现了冻融过程中岩块裂缝顶部及底部的微应变随冻融循环次数的增加而增加,岩样顶部的微应变在相同冻融循环次数下为底部的微应变的10倍左右的规律,建立了相同裂缝深度顶部裂缝微应变与冻融循环次数y=5.2288x2-160.9x+2484.1的定量关系。(4)基于散粒体斜坡形成速率的分析,对天山公路及中巴公路花岗岩、砂板岩、千枚岩及河谷堆积物等4种岩土体斜坡采取现场定点重复三维激光扫描,并对产屑率进行定量计算得到:河谷堆积物散粒体斜坡年产屑率0.0601(m3/3　)、千枚岩年产屑率0.0448(m3/3　)、砂板岩年产屑率0.0361(m3/3　)、花岗岩年产屑率0.0146(m3/3　),并揭示其夏秋两季产屑率低于冬春两季产屑率的规律。(5)基于降雨融雪作用下散粒体启动机理分析,结合现场调查和物理模拟试验,提出了波动S型、S脉冲型及脉冲型等3种启动模式,建立了冲刷深度y与雨强x所呈现的y=-6×10-5x2+0.0072x定量关系及流砂率与雨强间y=-3×10-7x3+3×10-5x2-0.0004x的幂次关系,总结了无粘粒散粒体斜坡以浅表层渐进前进式破坏模式,含粘粒散粒体斜坡以浅表层渐进前进式、中-深层溃决式破坏模式。(6)针对滚石冲击引起散粒体斜坡失稳机理问题,采取物理、数值模拟等手段,模拟了滚石能量与冲击频率对斜坡稳定性的影响,建立了散粒失稳质量与滚石质量2次幂函数定量关系;得到了冲击频率由5s增加到3s失稳质量增加约16.4%;频率从3s增加到1s失稳质量急剧增加至74.5%的现象,提出了高频率连续性冲击效应。(7)针对高寒山区散粒体斜坡转化为泥石流的特殊性进行分析,提出了孕育、灾变、发育、循环等四阶段灾害演化过程,揭示了含沙水流→稀性泥石流→粘性阵性流→粘性连续流→粘性阵性流→稀性泥石流→含沙水流等阶段运动过程,分析了阵流有“头”大、“身”平且短、“尾”细且长等特征,并建立了适宜于天山、中巴公路地区泥石流典型参数计算公式。
[Abstract]:The ramp of the granular body mainly consists of the slope body accumulated at the same magnitude and nearly uniform rock particles. Its material composition has the unique physical and mechanical characteristics, such as loose structure, high compression, strong water permeability, low cohesive force and so on. It has the characteristics of poor stability, strong recurrence and sudden high disaster formation, and the construction of highways and railway infrastructure in the alpine mountain area. Set, safe operation has a very important influence and even plays a crucial role in the local area. The scattered granular slope is mainly distributed in the alpine Canyon zone and the prone high intensity seismic area. It has a wide range of distribution, high frequency of recurrence, and a variety of chain reactions, especially the effect that can be easily converted into a series of disaster chains. At the same time, it also brings a lot of ecological environmental protection problems to the idea of establishing green channel in China. It can be seen that, with the large-scale promotion of infrastructure construction, the research on the evolution and catastrophe of the granular slope, as one of the geological disasters in the high cold mountain area, is not only for the disaster prevention and treatment of the mountain highway and other engineering facilities. In this paper, the Tianshan highway and the SINO pakistan highway are selected as a case of the study of the scattered granular slope in the high and cold mountainous areas. Based on the field investigation and investigation, the collection of geological environment and the literature retrieval, the distribution law and structure of the Tianshan highway, the central and Pakistan highway scattered grain slope and its structure are found out. Based on the special external dynamic effects of freezing thawing cycle and ice splitting in high and cold mountain areas, the microscopic transformation of circulating freezing thawing and ice splitting on the formation of bulk particles was studied, and the macro cracking mechanism was studied. The rate of debris production was measured and calculated by site fixed-point repeated three-dimensional laser scanning, and the lure of the dispersion of bulk particles was synthetically analyzed. The physical simulation and numerical simulation are adopted to verify the startup instability mode, the catastrophic mechanism and the accumulation characteristics of the granular slope under the rainfall melting and the rolling stone impact. The disaster chain effect of the granular chain reaction is analyzed, and the calculation formula of the typical characteristic parameter of the debris flow is summarized. In summary, this paper is aimed at the Tianshan highway. The study on the granular slope of the high and cold mountainous areas represented by the China Pakistan highway has systematically discussed the evolution process of the granular slope and the catastrophic effect. It provides the basic catastrophic mode and typical design parameters for this special type of slope engineering management. The main results are as follows: (1) from Tianshan highway, the central Pakistan highway dispersion grain oblique. On the basis of the distribution geological background of the slope, a detailed investigation of the debris slope along the highway has been carried out to obtain the spatial distribution law and the line density characteristics, and reclassified according to the characteristics of the scattered granular slope, and the two types of slope of the anclay particles and clay particles are added, and the incline granular granular slope is revealed. The typical characteristics are as follows: the particle size difference is larger, the gravity separation is obvious, the particles are mainly composed of gravel and breccia, the second is coarse sand, medium sand, almost no clay, loose cohesive force and so on. There are "two yuan structure" in the clay granular slope avalanche, and the structure of the slope is composed of two layers of the gravel layer and the bottom grain layer, and the upper gravel layer is in the upper layer. There is no cohesive force composed of rock and gravel, and there is a certain cohesive force at the bottom. The formation process of the non clay granular granular slope can be induced by high peeling, accumulation and movement and slipping, and the formation of clay granular slope can be induced by a series of processes, such as high peeling, accumulation and migration, rock freezing thawing decomposition, leaching and consolidation, creep and so on. (2) through the freezing and thawing cycle conditions rock The microfracture expansion of stone is studied in detail and deeply. The early strength of three types of rock (granites, phyllite, sandstone) of three kinds of working conditions (granites, phyllite, sandstone) has been rapidly increased and the later strength gradually decreased, and a few mineral components migrated into and closed some micro fissure space in the early freeze-thaw rock. In order to improve the strength of rock, the micro fissure of closed rock in the late freezing and thawing period is partially through after several cycles, and the later strength is reduced. (3) based on the deterioration characteristics of the rock structure surface in the alpine mountain area, the ice splitting test of the self made fissure in the rock mass is adopted, which reveals that the rock body shape can be summed up as freezing shrinkage, frost heave and thawing and thawing process. The freezing thawing process is found. The micro strain at the top and bottom of the rock mass increases with the increase of the number of freezing and thawing cycles. The micro strain at the top of the rock sample is about 10 times of the micro strain at the bottom of the same freeze-thaw cycle. The quantitative relationship between the crack micro strain and the number of freezing and thawing cycles at the top of the same crack depth is established. (4) based on the quantitative relationship between the cracks at the top of the same crack depth and the number of freezing and thawing cycles y. In the analysis of the formation rate of the debris, the site fixed point repeated three-dimensional laser scanning is taken on 4 slopes of the Tianshan highway and the granite, the sands, the phyllite and the river valley deposits, and the ratio of the debris yield is 0.0601 (m3/3?) and the annual yield rate of the phyllite. 0.0448 (m3/3?), the annual crumb rate of sand slate is 0.0361 (m3/3?), the annual yield rate of granite is 0.0146 (m3/3?), and the yield rate of the two quarter of summer and autumn is lower than that of the winter and spring two seasons. (5) based on the analysis of the starting mechanism of the granular bulk under the rain and snow melting, combined with the present field investigation and physical simulation test, the wave S, the S pulse type and the pulse are put forward. The quantitative relationship between the scouring depth y and the y=-6 x 10-5x2+0.0072x presented by the scouring depth y and the rain intensity x and the power relation between the flow sand rate and the rain strong y=-3 x 10-7x3+3 x 10-5x2-0.0004x are established. The progressive progressive failure mode of the non clay granular slope with shallow surface is summed up, and the clay granular granular slope is progressively advancing on the shallow surface. 6. (6) in view of the mechanism of the slope instability caused by the rolling stone impact, the effects of the rolling stone energy and the impact frequency on the slope stability are simulated by means of physics and numerical simulation, and the quantitative relationship between the mass and the 2 power function of the rolling stone is established, and the impact frequency is increased from 5S to 3S The instability mass increased by about 16.4%, the frequency increased from 3S to the 1s instability mass to 74.5%, and the high frequency continuous impact effect was put forward. (7) to analyze the particularity of the debris flow into the debris flow in the alpine mountain area, and put forward the four stages of the evolution process, such as inoculation, catastrophe, development and circulation, and revealed the sediment laden flow. The movement process of the lean debris flow, viscous flow, viscous continuous flow, sticky formation flow, thinner debris flow and sediment laden flow, analyzed the characteristics of "head" big, "body" flat and short, "tail" and long and so on, and established a formula for calculating typical parameters of debris flow in Tianshan Mountain and the central Pakistan highway area.

【学位授予单位】：成都理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P642.2

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