IMHE OpenIR  > 山地灾害与地表过程重点实验室
滚石冲击动力反演与棚洞优化设计研究
Alternative TitleImpact Dynamic Inversion of Rockfall and Optimization Design of Rock-shed
Language中文
闫帅星
Thesis Advisor何思明
2016
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Name硕士
Keyword滚石 棚洞 动力响应 冲切 反演
Other Abstract

滚石灾害已经成为继滑坡、泥石流灾害之后的第三大次生山地灾害,具有分布范围广、发生突然、频率高、大变形、冲击破碎等特征,并伴随复杂能量转化,因此,对滚石灾害的防治一直是近年来的研究热点之一。棚洞工程在众多滚石灾害防护措施当中,凭借其优良性能被广泛应用于实际工程。但目前我国在滚石灾害及其防治方面的研究基础相对薄弱,对棚洞结构的减灾机理仍需明确。基于此,论文针对棚洞结构研究中尚存的问题,系统开展滚石冲击钢筋混凝土棚洞板动力响应理论方法及数值研究,并在此基础上进行棚洞板抗冲切设计及反演分析,进一步为棚洞结构防灾设计提供技术支持。论文取得了如下成果:(1)提出基于弹塑性接触的滚石冲击棚洞板动力响应的一般理论解法以弹塑性接触理论和正交各向异性板的动力控制方程为基础,引入Huber近似,构建滚石冲击荷载下棚洞板动力响应公式,提出了滚石冲击荷载下棚洞板动力响应的一般理论解法,并通过有限元数值模拟验证了该方法的准确性。最后基于该理论方法,研究滚石冲击到棚洞板不同特征位置处的响应规律,确定以冲击承载力为依据的最不利荷载条件并非棚洞板中心位置而是在板的边缘,原因与约束条件有关。(2)钢筋混凝土棚洞板抗冲切承载力影响因素分析针对实际工程案例,基于有限元方法得到的滚石施加在棚洞板上的最大冲击荷载,进行抗冲切验算,系统比较了我国规范、美国规范以及考虑配筋率影响的计算模型三种计算方法的异同,并就滚石冲击力和钢筋混凝土板抗冲切承载力的影响因素进行了敏感性分析,为棚洞结构的抗冲切设计提供依据。(3)提出新型棚洞结构形式中耗能器的优化设计方法提出通过对新型棚洞结构中的金属耗能器进行顶部开孔设计来设置初始损伤的优化设计方法,构建了三维参数化有限元模型,研究了不同初始损伤模式下金属耗能器的破坏模式、冲击力-位移响应关系及其耗能效果。结果表明,顶部开孔可以有效降低初始屈服荷载而不影响其耗能效果。(4)滚石冲击棚洞结构动力反演分析方法讨论系统研究冲击反演设计方法的共性与特性,将机械冲击反演与计算智能优化的应用领域拓展到棚洞结构的优化设计研究当中,构建出滚石质量及冲击速度等的反演设计思路,为滚石特征预测及结构防护提供理论支撑。

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Rock-shed structures are widely used in practical engineering of rock-fall protection, because of its excellent properties among numerous rock-fall protection measures. However at present the research of our country in rock-fall disasters as well as their prevention and control is relatively weak, the disaster reduction mechanism of rock-shed structure still need to be clearer. Based on this, this paper aiming at the remaining problems in the research of rock-shed structure, and the system to carry out the theory of dynamic response of reinforced concrete rock-shed plate method and numerical research is built, which forms the basis of RC plate cutting resistance and inversion analysis, further to provide technical support for the rock-shed structure of rock-fall disaster prevention design. The paper has achieved the following results:(1) A general theoretical method of impact response of rock-shed RC slab based on elastic-plastic contact theory is proposedBased on the composite plate response, a general calculation method of impact response of rock-shed RC slab which is structurally orthotropic was presented, where Huber’s approximation was introduced into the classical plate equations combined with a developed three phase elastoplastic contact law accounting for permanent indentation. Finite element stimulation was used for verification. Responses of different impact positions were studied, with the maximum indentation, maximum impact force, maximum deflection and the permanent indentation were compared. Results show that, from the edge to the midline of the slab, αm, Fm and αf decrease approximate linearly and reach the minimum values on the midpoint while the wm gets the maximum value.(2) The influencing factors of the punching resistance of rock-shed RC slabs are compared and analyzedDirect against practical engineering cases, based on the maximum impact forces applied on rock-shed RC slabs under axial impact of rock-falls, which are obtained by finite element method, three kind of calculation methods of punching resistance of the slab are compared, including China standard (GB50010-2010), the United States standard (ACI318-08) as well as the calculation model considering the influences of reinforcement ratio proposed by Menétrey. And the influence factors of impact force and punching resistance of the RC slab are analyzed, which provides the basis of the punching design of the rock-shed structure.(3) Put forward an optimization design of the metal energy absorbers in new-typed rock-shedA new metal energy absorber with initial damage is proposed to reduce the maximum load while maintaining the effect of energy absorption. The dynamic response of metal absorbers with different initial damage modes under axial impact is studied by LS-DYNA, with failure modes, force-displacement response and energy dissipation are compared. Results show that, reasonable initial damage can effectively reduce peak yield load up to 40%, while average collapse load, total energy absorption remain basically unchanged, and thus the metal energy absorber is optimized.(4) The inverse calculation methods for rock-fall impact on RC slabs are discussedSystematic study the commonness and characteristics of inverse design methods, and expand to the application of the rock-shed structure optimization design study. Build inversion calculation method of the quality and impact velocity of rock-fall, which could provide theoretical support to the rock-fall characteristics forecasting and impact rebounding property description. 

Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/18878
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
闫帅星. 滚石冲击动力反演与棚洞优化设计研究[D]. 北京. 中国科学院大学,2016.
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