【摘要】：針對被動柔性防護(hù)網(wǎng)在實際工程中承受累計沖擊的現(xiàn)狀,開展標(biāo)稱能級為1 500 kJ的防護(hù)網(wǎng)結(jié)構(gòu)足尺落石試驗,在無修復(fù)狀態(tài)下進(jìn)行連續(xù)累加沖擊;基于LS-DYNA的顯式算法,對試驗進(jìn)行全過程模擬;進(jìn)而采用數(shù)值分析開展標(biāo)稱能級為750,3 000和5 000 kJ系統(tǒng)的累計沖擊模擬。結(jié)合試驗與數(shù)值仿真研究累計沖擊作用下,結(jié)構(gòu)的傳力機(jī)制、變形特征、耗能分布。結(jié)果表明:中跨已成功攔截1 500 kJ落石沖擊的被動柔性防護(hù)網(wǎng),仍具有繼續(xù)承受左跨750 kJ、右跨750 kJ和中跨1 500 kJ共4次連續(xù)沖擊能力。系統(tǒng)的沖擊力學(xué)行為具有明顯的三階段特征,隨著累計沖擊的開展,系統(tǒng)的主要耗能由第二階段轉(zhuǎn)換為第三階段;減壓環(huán)的耗能比例降低,網(wǎng)片的耗能比例提高;結(jié)合各工況的性能曲線,建立系統(tǒng)的能量儲備系數(shù)與各階段能量比例的相關(guān)計算公式,采用該公式可對系統(tǒng)的能量儲備進(jìn)行預(yù)估,研究結(jié)果為被動柔性防護(hù)網(wǎng)結(jié)構(gòu)的設(shè)計提供理論基礎(chǔ)。
[Abstract]:In view of the current situation that passive flexible protective net is subjected to accumulative impact in actual engineering, the full-scale rockfall test of protective net structure with nominal energy level of 1 500 kJ is carried out, and continuous accumulative impact is carried out in the condition of no repair. Based on the explicit algorithm of LS-DYNA, the whole process of the experiment is simulated, and the accumulative shock simulation of the system with nominal energy levels of 750,3000 and 5,000 kJ is carried out by numerical analysis. Combined with test and numerical simulation, the force transfer mechanism, deformation characteristics and energy dissipation distribution of the structure under accumulative impact are studied. The results show that the passive flexible protective net which has successfully intercepted 1 500 kJ rockfall impact still has the ability to withstand four consecutive impacts of left and right span 750 kJ and middle span 1 500 kJ. With the development of accumulative impact, the main energy consumption of the system changes from the second stage to the third stage, the proportion of energy consumption of the decompression ring decreases and the energy consumption ratio of the mesh increases. Combined with the performance curve of each working condition, the formula of calculating the energy reserve coefficient and the energy ratio of each stage is established, and the energy reserve of the system can be predicted by the formula. The results provide a theoretical basis for the design of passive flexible protective net structure.
【作者單位】： 西南交通大學(xué)土木工程學(xué)院;成都理工大學(xué)地質(zhì)災(zāi)害防治與地質(zhì)環(huán)境保護(hù)國家重點實驗室;西南石油大學(xué)土木工程與建筑學(xué)院;
【基金】：國家自然科學(xué)基金資助項目(51408498) 成都理工大學(xué)地質(zhì)災(zāi)害防治與地質(zhì)環(huán)境保護(hù)國家重點實驗室開放基金資助項目(SKLGP2016K013) 中央高�；究蒲袠I(yè)務(wù)費專項資金資助項目(2682017CX006)~~
【分類號】：P642.2

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