被动柔性落石防护网结构冲击力学行为与设计理论

Passive flexible rockfall restraining nets are widely applied to prevent rockfall hazard along railway and highway lines, especially in the mountain road.However，the current status of the passive flexible rockfall restraining nets cannot be proved effective protection due to insufficient basic research to support. The study focuses on the following issues and devotes to solve them: the theoretical analysis model and main influence factors of rockfacll impact load, the mechanical behavior of flexible rockfall restraining nets, the nonlinear simulation of systematic computation, safety evaluation method of anti-rockfall impact, and anti-impact design method for matching rockfall energy. This study aims to establish a reliable mathematical expression for rockfall impact load,propose the analysis theory of impact damage under overall coordination and the safety assessment methods under impact load for important components, verify the effectiveness of flexible rockfall restraining nets under impact load and investigate its mechanical behavior, eventually establish the design method based on energy matching theory. The ultimate purpose is to improve the performance of rockfall hazard prevention and protect the safety of maintain traffic lines to reduce the loss of life and property. investigate its mechanical behavior, eventually establish the design method based on energy matching theory. The ultimate purpose is to improve the performance of rockfall hazard prevention and protect the safety of maintain traffic lines to.reduce the loss of life and property.

被动柔性防护网广泛用于山区公、铁交通沿线的落石灾害防护。项目针对目前国内柔性防护网结构由于基础研究匮乏导致无设计理论支撑，进而造成无法有效安全防护的现状，着力研究并解决以下问题：考虑随机性的落石冲击荷载模型、柔性防护网系统的抗落石冲击力学行为、落石冲击作用下的整体协同非线性数值计算理论、损伤条件下柔性防护网的抗落石冲击安全性评估方法、基于能量匹配的柔性防护网抗落石冲击设计方法。通过研究：建立简明可靠的落石冲击荷载数定表达式；建立及落石-防护网冲击动力学模型与柔性网结构整体协同作用条件下的冲击动力分析理论；构建冲击荷载作用下主要部件的安全性评估方法；探明冲击荷载作用下柔性防护网的力学行为和抗冲击效果；建立柔性网结构的能量匹配理论及设计方法。以期提高我国的落石灾害防治水平，保障山区交通干线的运营安全，减少国家和人民的生命财产损失。

被动柔性防护网广泛用于山区交通沿线的落石灾害防护。目前国内柔性防护网结构由于基础研究匮乏导致无设计理论支撑，进而造成无法有效安全防护的现状。.本项目通过足尺试验、数值模拟、野外调查，研究了：考虑随机性的落石冲击荷载模型、柔性防护网系统的抗落石冲击力学行为、落石冲击作用下的整体协同非线性数值计算理论、损伤条件下柔性防护网的抗落石冲击安全性评估方法、基于能量匹配的柔性防护网抗落石冲击设计方法等五个方面的问题。分别开展了高强钢丝静力拉伸试验，环形网片水平拉伸试验、拟静力顶破试验，环形网片动力冲击试验，环式耗能器拟静力、动力冲击试验及棒式耗能器的拟静力、动力冲击试验等一系列关键部件试验，还开展了750kJ、1500kJ、2000kJ、3000kJ、5000kJ能级的被动网足尺冲击试验。研究了考虑旋转能量、冲击位置等随机性落石、碎屑流荷载作用下柔性防护网系统及部件的抗冲击力学行为；建立了冲击荷载下柔性网结构整体协同工作条件下的非线性有限元FEM，对冲击荷载作用下柔性防护网的力学行为和抗冲击性能进行了定量描述及参数分析，此外，探索了颗粒体冲击防护网的离散元DEM、光滑粒子流体动力学SPH耦合数值模型；针对关键部件进行了理论研究，推导了综合多因素影响下环形网片变形能力、承载能力、耗能能力安全性能指标的计算公式与快速选型方法，形成了防护系统及其主要部件的安全性评估方法；结合野外实地调查与工程案例分析，分析了被动柔性防护网典型破坏机理，提出了柔性网结构基于能量匹配的设计方法，明确了设计原则与设计流程。.通过本课题的研究，在被动柔性防护网拟静力-动力部件试验及足尺冲击试验，随机落石荷载冲击防护网的非线性有限元数值模型，落石-防护网相互作用机理与结构响应等几个基础科学问题上取得重要进展，为被动柔性防护网设计提供了理论支撑，提高了我国的落石灾害防治水平。