【作者】 李维光；

【导师】 张继春；

【作者基本信息】 西南交通大学 ， 岩土工程， 2008， 博士

【摘要】 随着社会的进步、国民经济的发展，在公路、铁路、水利水电、露天矿山等建设中经常遇到顺层边坡，同时顺层边坡也是危害性最大、治理最难的边坡。采用拟静力法时，如何合理选择拟静力系数，以评价和研究爆破震动效应对顺层边坡的影响已成为当前岩土工程界、爆破工程界亟待解决的一项重要课题。结合峨嵋水泥厂石灰石露天矿山的工程实际，以及爆破的特点，设计小型爆破振动试验台，采用理论推导、实验室模拟试验、现场实际爆破设计相结合的手段，较为系统地研究了爆破荷载作用下顺层边坡的稳定性问题。（1）分析了影响顺层岩质边坡变形破坏的主要因素。鉴于滑坡体系统的静力稳定性分析方法已经成熟，而滑坡体系统在爆破荷载作用下的稳定性问题尚处于探讨之中。所以，拟静力法常被采用来分析研究边坡的稳定性安全系数。（2）采用极限平衡法，按照摩尔一库仑准则，建立了顺层岩质边坡在作用于条块质心爆破荷载、边坡表面卸荷载作用下稳定性安全系数的数学表达式。①从爆破荷载作用方向看，水平向外爆破荷载、垂直向下爆破荷载以及水平方向夹角较大的水平向外爆破荷载和垂直向下爆破荷载的联合爆破荷载不利于顺层边坡稳定。②天然状态的潜在滑坡体受水平向外爆破荷载作用时，顺层岩质边坡体的稳定性安全系数与水平向外爆破荷载拟静力系数间呈负指数关系：水平向外爆破荷载拟静力系数每从0起增加0．05，存在层裂长度的顺层边坡稳定性安全系数减少7．786％-10．665％，不存在层裂长度的顺层边坡稳定性安全系数减少7．61％-10．546％。③当潜在滑坡体处于天然状态时，顺层岩质边坡体的稳定性安全系数与垂直向下爆破荷载拟静力系数间呈S曲线关系：垂直向上爆破荷载拟静力系数从0起每增加0．05，顺层边坡稳定性安全系数将增加2％-3．5％。所以，垂直向上爆破荷载对顺层边坡稳定的影响很小。④潜在滑坡体受到垂直向下或水平向外联合爆破荷载作用时，当潜在滑坡体处于饱水状态时，随着联合爆破荷载拟静力系数不断增加，处于失稳状态边坡的稳定性系数不断减少；当垂直向下爆破荷载一定时，顺层边坡稳定性安全系数与水平向外爆破荷载拟静力系数间呈负指数关系，顺层边坡稳定性安全系数与垂直向下爆破荷载拟静力系数间呈S曲线关系。⑤爆破层裂效应对顺层边坡的稳定起着劣化作用，减低了顺层边坡的稳定性。在其它相同条件下，天然状态顺层边坡安全系数随着爆破层裂长度的增加而线性减少，尤其是在滑移面长度小于20m时最明显：在其它相同条件下，顺层边坡安全系数随着滑移面粘结力的增加而明显增大，当滑移面粘结力小于60kPa时影响最明显;在其它相同条件下，顺层边坡安全系数随着滑移面内摩擦角的增加而明显增大，当滑移面内摩擦角小于20°时影响最明显。⑥当潜在滑坡体处于天然状态时，爆破荷载对顺层边坡稳定性的影响，不仅体现在爆破荷载的大小上，而且体现在爆破荷载的作用方向上。当潜在顺层岩质滑坡体受到振动垂直向下、水平向外联合爆破荷载联合作用时，联合爆破荷载与水平方向夹角较大者有利于顺层岩质边坡的稳定。（3）建立了顺层岩质边坡运动的简单力学模型。只有加速度为负时，潜在滑坡体系统才可能处于稳定状态。但影响潜在滑坡体系统处于稳定状态的因素很多，这些因素的变化及其作用，促使Fcos（α-β）+wsinα、T（v₀）之间平衡关系发生变化，从而造成滑坡体系统稳定性的变化。（4）根据相似模拟原理，设计的爆破振动模拟装置可模拟垂直方向、水平方向以及垂直和水平联合作用任意方向时的爆破振动试验台。爆破振动试验台与模拟对象无关，可模拟顺层岩质边坡在爆破荷载作用下的爆破振动。①在垂直向下爆破荷载作用下，垂直振动速度与处于极限平衡状态顺层边坡潜在破坏面倾角呈对数关系而与潜在滑移面内摩擦角弱化值间呈线性关系。②在相同垂直振动速度、频率条件下，潜在滑移面静摩擦角与静摩擦角弱化值间呈线性关系，潜在滑移面静摩擦弱化值与垂直向下爆破振动频率间呈幂函数关系。③在水平向外爆破荷载作用下，不同潜在滑移面强度条件下，一方面垂直振动速度与潜在滑移面坡面角间呈对数关系，垂直振动速度与潜在滑移面坡面内摩擦角弱化值间呈线性关系。④在水平向外爆破荷载作用时垂直振动速度一定时，顺层边坡潜在滑移面粘结力与垂直振动速度呈对数关系，内摩擦角与潜在滑移面坡面角间呈线性关系。⑤当不同状态顺层边坡受到不同垂直振动速度的水平向外爆破荷载作用时，处于极限平衡状态顺层边坡潜在滑坡体承受的水平向外爆破荷载拟静力系数高达数十倍到数百倍，即不同状态的顺层边坡受到不同垂直振动速度的水平向外爆破荷载作用时，其水平向外爆破荷载是顺层边坡潜在滑坡体重量的数十倍到数百倍。在一定顺层边坡坡面角条件下，当顺层边坡在一定垂直振动速度的水平向外爆破荷载作用时，其水平向外爆破荷载拟静力系数与顺层边坡潜在坡移面内摩擦角间呈线性关系：随着顺层边坡潜在坡移面内摩擦角的不断增加，水平向外爆破荷载拟静力系数不断减少。（5）当顺层岩质边坡受到水平向外爆破荷载作用而产生7、8 cm/s的垂直振动速度时，其爆破荷载拟静力系数不超过0．3，即采用强度弱化法时爆破动力折算系数5．25‰、3．28‰，采用等效安全系数法时爆破动力折算系数0．242‰、0.154‰，顺层岩质边坡将处于稳定状态。同时，得出爆破动力折算系数与垂直振动速度间相互关系，从而确定不同垂直振动速度下水平向外爆破荷载拟静力系数。采用相同爆破动力折算系数，这样可能造成随垂直振动速度不同而顺层边坡稳定性安全系数、边坡状态出现差异很大。说明必须考虑爆破动力折算系数，以修正爆破荷载拟静力系数。更多还原

【Abstract】 With the rapid progress of the society and with the rapid development of our national economy, the infrastructure industry, such as highway, railway, water conservancy and hydropower engineering, and strip mine always meet layered slope, which is the most hazardous and the most difficult to be treated. Using the pseudo-static method, how to select the reasonable pseudo-static coefficient to evaluate and research the influence of blasting vibration on the layered slope becomes a hot problem concerned by rock mass field and blasting engineering field. Combining with the practical engineering of limestone strip mine of Emei cement plant and the characteristic of blasting, the mini-type blasting vibration test-bed was designed. The stability of layered slope with weak intercalation caused by blasting was systemically analyzed based on the theory deductions, experiments in laboratory and the in-site blasting test.1. Analyzed the main factors effected the deformation and failure of the layered rock slope. Because the static analysis methods of landslide system had been fully developed, and the stability analysis methods under blasting were still at a stage of exploration, the pseudo-static analysis method was often used to calculate the safety factor of slope stability.2. Based on the Mohr-Column criteria, the explicit expression of the safety factor of layered slope stability was deduced by method of limit analysis under the blasting load acting on the center of slice mass and the unload of surface of slope.（1） From the viewpoint of the direction of blasting load, the outwards horizontal blasting load, the downwards vertical one as well as their combined one were disadvantageous to the stability of layered slope.（2） There was a negative exponential relationship between the safety factor of layered slope stability and the pseudo-static coefficient of the outwards horizontal blasting load, when the potential landslide under the nature condition was acted on the outwards horizontal blasting load. When the pseudo-static coefficient of the horizontal load was added 0.05 from 0 to 0.3, the safety coefficient of layered slope with or without stratification cracking was reduced 7.786% to 10.665% and 7.61% to 10.546%, respectively.（3） When the potential landslide was under the nature condition, the relationship between the safety factor of layered slope stability and the downwards vertical blasting load submitted to the curve of s. When the pseudo-static coefficient of the upwards vertical load was added 0.05 from 0 to 0.3, the safety coefficient of layered slope was reduced 2% to 3.5%. So, the upwards vertical blasting load influenced little on the stability of layered slope.（4） When the potential landslide under the nature condition was acted on the outwards horizontal and downwards vertical blasting loads, with the increase of the pseudo-static coefficient of the combined blasting load of outwards horizontal one and the downwards vertical one, the safety factor of layered slope in instability condition reduced continuously. When the downwards vertical blasting load was invariable, the relationship between the safety factor of layered slope stability and the pseudo-static coefficient of the outwards horizontal blasting load and downwards vertical one submitted to the curve of negative exponential and s, respectively.（5） The stratification cracking effect had a bad influence on the stability of layered slope and reduced its stability. Under the same other terms, the stability of layered slope linearly reduced with the increase of length of stratification cracking, and especially, the reduction was the most obvious when the length was less than 20m. Under the same other terms, the stability of layered slope clearly increased with the increase of cohesive force of sliding interfaces, and especially, the influence was the most obvious when the cohesive force was less than 60KPa. Under the same other terms, the stability of layered slope clearly increased with the increase of internal friction angle of sliding interfaces, and especially, the influence was the most obvious when the internal friction angle was less than 20°.（6） When the potential landslide was under the nature condition, the influence of blasting load on the stability of layered slope not only related to the level of blasting load, but also related to the action direction. When the potential layered rock slope was acted on the outwards horizontal and downwards vertical blasting loads, the angle between the direction of load and the horizontal direction was beneficial to the stability of layered rock slope.3.The simple motion mechanics model of layered rock slope was established. Only when the acceleration was less than zero, the potential landslide system could be in a stable state. But there were various factors that could affect the stability of the potential landslide system, and the change of factors and theirs effects induced the change of equilibrium between F cos（α-β） + w sinαand T （v₀）, even induced the change of stability of the potential landslide system.4. According to the similarity principle of the simulation, the mini-type blasting vibration test-bed was designed, which could simulate the blasting vibration of vertical direction, horizontal direction and arbitrary direction. The blasting vibration test-bed was independent on the simulation objects, and could simulate the vibration of layered rock slope under blasting.（1） When the potential landslide was acted on the downwards vertical blasting load, the relationship between velocity of vertical vibration and obliquity and decrement of internal friction angle of sliding interfaces of layered slope in limit equilibrium state obeyed the logarithm law and linearity law, respectively.（2） When the velocity and the frequency of vertical vibration were invariable, the relationship between the angle of static friction and its decrement obeyed linearity law, and the relationship between the frequency of vertical vibration and the decrement of static friction angle submitted to the curve of power function.（3） When the potential interface under different intensity condition was acted on the outwards horizontal blasting loads, the relationship between the velocity of vertical vibration and the of obliquity of potential interface and the decrement of the internal friction angle submitted to the curve of logarithm function and linearity, respectively.（4） When the velocity of vertical vibration acted on the outwards horizontal blasting loads were invariable, the relationship between the velocity of vertical vibration and the cohesive force of potential interface submitted to the curve of logarithm function, and the relationship between the obliquity of potential interface and the internal friction angle submitted to the curve of linearity function.（5） When the layered slope in different condition was acted on the outwards horizontal blasting load with different velocity of vertical vibration, the pseudo-static coefficient of the potential landslide system in limit equilibrium state was tens times to hundreds times. When the layered slope with the obliquity invariable was acted on the outwards horizontal blasting load, the relationship between the pseudo-static coefficient of the outwards horizontal blasting load and the internal friction angle of sliding interfaces of layered slope obeyed the linearity law, that was to say, the pseudo-static coefficient of the outwards horizontal blasting load decreased with the increase of internal friction angle.5. When the velocity of vertical vibration of the layered rock slope was 7or 8 cm/s, the pseudo-static coefficient of the blasting load was less than 0.3, that was to say, blasting dynamic reduction coefficient was 5.25‰or 3.28‰when strength reduction method was accepted, blasting dynamic reduction coefficient was 0.242‰or 0.154‰when equivalent safety coefficient method was accepted, and the slope was in stabile condition. Meantime the relation between the velocity of vertical vibration and blasting dynamic reduction coefficient was obtained, therefore the pseudo-static coefficient of the outwards horizontal blasting load was determined under different velocity of vertical vibration. Generally, using the same blasting dynamic reduction factor would lead to the safety factor of layered slope stability much difference with the difference of the velocity of vertical vibration, which indicated that the blasting dynamic reduction factor must be taken into account to modified the pseudo-static coefficient of the blasting load.更多还原