活塞杆点支式柔性缓冲系统冲击力学行为

针对公路、铁路沿线棚洞结构的落石防护问题，提出了活塞杆点支式柔性缓冲系统，该系统支撑于棚洞结构顶部，由缓冲器、环形网、支撑绳、活塞杆组成，对棚洞结构起缓冲防护作用。为研究缓冲系统冲击力学行为，设计了子结构模型，开展了25kJ能量冲击试验，结合动力非线性分析，研究了子结构模型的冲击变形、传力途径、内力响应以及缓冲消能特性。研究表明：活塞杆点支式柔性缓冲系统可有效实现落石防护，系统具有松弛变位、顶紧压缩、回弹释放三阶段变形特征，可实现缓冲、自复位及落石的可引导弹出；与普通钢压杆支撑模型相比，子结构模型的冲击力作用持时延缓67%，冲击力峰值降幅达30%；在相同冲击能量下，与砂土缓冲垫层和EPS缓冲垫层的冲击力相比，子结构模型冲击力峰值降幅分别达到69%和61%。最后，通过弹簧刚度参数分析，拟合得到子结构模型的性能曲线及其P-s相关方程。

Mechanical behavior of piston rod point-supported flexible buffer system

To solve the rockfall protection problems of rock-sheds along highways and railways, a piston rod point-supported flexible buffer system is proposed. Consisting of buffers, ring nets, support ropes and piston rods， the buffer system is supported on the top of a rock-shed and can provide buffer protection for the rock-shed structure. To study the mechanical behavior of the buffer system, a substructure model was designed and an impact test of 25kJ was carried out. The loading path and deformation feature, as well as the internal force response and system buffering characteristics were emphatically analyzed in combination with the test and numerical simulation. The results show that the substructure can successfully intercept a block with impact kinetic energy of 25kJ. The buffering process is characterized by three stages, i.e. relaxation deformation, compression deformation and deformation resilience. Compared with the steel column support model, the piston rod point-supported buffer system can reduce the maximum impact force by about 30%, and increase the impact time by 67%. Meanwhile, compared with those of the sand cushion layer and the EPS cushion layer, the maximum impact force of the substructure model reduces by about 69% and 61% respectively under the same impact energy. By adjusting the system configuration, the performance curve and the corresponding approximate formula are obtained under different spring stiffness conditions.