IMHE OpenIR  > 山地灾害与地表过程重点实验室
滚石冲击下棚洞结构的动力响应
Alternative TitleThe dynamic response of the shed hole structure under the impact of the rolling stone
张文成
Thesis Advisor何思明
2013
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name硕士
Degree Discipline防灾减灾工程及防护工程
Keyword滚石冲击 棚洞 耗能器 Eps垫层 Ls-dyna
Abstract我国西部山区是地质灾害多发区,地震、泥石流、滑坡等地质灾害引发的山体崩塌、滚石抛落的灾害时常发生,造成的桥墩砸断、公路瘫痪事故日益突出,因而对滚石灾害进行防护研究有着非常重要的工程意义。 棚洞板防护结构,凭借其低廉的成本和较好的力学性能被广泛用于滚石灾害防护。随着棚洞应用数量的不断增加,其安全性和稳定性越发值得重视。从设计单位反馈的信息来看,工程应用中由于棚洞结构设置不当而被砸坏的案例屡见不鲜,因此,研究滚石冲击力和棚洞的抗冲击动态响应特性,对选择合适的棚洞结构具有非常重要的意义。 为减少滚石冲击的最大冲击力及最大程度的缓冲耗散滚石冲击能,研究者提出了几种新型耗能棚洞。其中一种是新型耗能器棚洞结构,它由钢筋混凝土板(不覆盖缓冲垫层)和支撑混凝土板的吸能支座组成。另一种是EPS垫层棚洞,该棚洞结构通过在钢筋混凝土板上覆盖一层EPS泡沫材料来达到耗能减震的目的。 本文以显式有限元理论(Explicit FEM)为基础,基于大型显式有限云程序LS-DYNA,对普通棚洞、耗能器棚洞及EPS垫层棚洞在滚石以15m/s的速度冲击下的动态响应进行了有限元模拟,比较了滚石冲击位置在棚洞板中点和边缘位置两种情况,分析了各种情况下三种棚洞板结构中最大应力传递过程、能量转换过程、冲击力历时过程及支座应力的历时过程。研究得出了以下结论: (1)在滚石冲击下,普通棚洞钢筋混凝土板内的应力传递是由冲击点处向两侧扩散的;耗能器棚洞板在碰撞开始后一段时间是由冲击点处向两侧扩散,但当能量传递到耗能器后,应力的传递主要在耗能器上进行;对于EPS垫层棚洞,应力的传递则是由支座处向棚洞中间扩散。 (2)EPS垫层棚洞的耗能效果是最好的,且其能延长滚石与棚洞的作用时间,大大缓冲了滚石对棚洞的冲击力,从而对棚洞起到了很好的保护作用。 (3)耗能器棚洞的耗能效果没有EPS垫层棚洞可观,但其能够有效缓冲滚石冲击对支座的压力,保护支座不受破坏。 (4)冲击位置越靠近棚洞边缘,耗能器棚洞的耗能减震效果发挥的越好。
Other AbstractGeological disasters are common in western mountainous areas of our country where mountain collapse and rock-falls are always induced by earthquakes, landslides, debris flow and other geological disasters. The cost of destruction of highways and bridges caused by geological disasters is increasing rapidly these years. Therefore it is of great significance to study the rock-falls protective structures. As a low-cost, simple and effective protective structure against rock fall,rock-shed hole been used more and more widely nowadays. With the increasing number of its applications, security and stability of the structure are more worthy of attention. However, Many shed hole were destroyed as unreasonable structure settings judging from feedbacks of construction sectors. So,studying rock-fall impact force and shed hole’s dynamic response characteristics has very important significance to choose the appropriate shed hole structure. Researchers have proposed several new energy dissipation shed hole structure to reduce the maximum impact force and dissipate rock-fall impact energy. One is damper shed hole structure,which consists of a reinforced concrete slab (not covered by any cushion) and cylindrical shell supports designed to dissipate the energy of rocks hitting on the edge of the slab. Another is EPS cushion shed hole,whose reinforced concrete slab has covered with a layer of EPS foam. Based on the theory of dynamic explicit Finite Element Method (FEM) and LS-DYNA program,we study the dynamic response of ordinary shed hole,damper shed hole and EPS cushion shed hole with rock-fall’s impact speed of 15m/s using finite-element method. By comparing the impact location at the middle and the edge of shed hole plate,we have analyzed maximum stress transfer process,energy conversion process,impact force’s diachronic process and bearing stress’s diachronic process of the three kinds of shed hole plate structure. The numerical results show that: (1) Under the rock-fall’s impact, the maximum stress transfer from the point of impact position to both sides of reinforced concrete slab in ordinary shed hole. While in damper shed hole, the maximum stress first propagates in the shed hole plate. When it reaches the damper device, it is mainly spread in the damper device. To EPS cushion shed hole, its maximum first appears in the pedestals, then transfers to the middle. (2) EPS cushion shed hole’s energy dissipation effect is best, besides, it could extend the contact time between rock-fall and shed hole, which greatly reduced the impact force to protect the shed hole structure. (3) The damper shed hole’s energy dissipation effect is less than EPS cushion shed hole, but it can effectively buffer the impact of rolling pressure on the pedestals. (4) The impact location closer to shed hole edge, the better played of the damper shed hole’s energy dissipation effect.
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/6983
Collection山地灾害与地表过程重点实验室
Recommended Citation
GB/T 7714
张文成. 滚石冲击下棚洞结构的动力响应[D]. 北京. 中国科学院研究生院,2013.
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