摘要:
为提升既有危化品库、弹药库等设施围护结构的抗爆性能,建立了一种钢板混凝土夹芯砌体防爆墙构造用于墙体改造。并采用数值模拟的方法,以未加固的砌体填充墙和基于钢板混凝土叠合式砌体防爆墙为研究对象,利用动力非线性有限元分析软件ABAQUS/Explicit开展爆炸荷载作用下砌体墙的动态响应试验研究。其中,砌筑墙体、现浇混凝土、爆炸当量(TNT)和夹芯钢板均为实体单元类型,钢筋网为梁单元类型;钢筋网嵌入现浇混凝土中,砌筑墙体、现浇混凝土、夹芯钢板之间均采用面-面接触;在接触属性中,采用罚函数(Penalty),摩擦系数为0.75,砌块间的黏结滑移采用指数损伤演变本构;结构模型采用完全约束类型对墙体底部与顶部进行约束,并采用精细有限单元划分网格,尺寸大小划分为0.01 m。通过对未加固和采用夹芯钢板混凝土叠合加固的砌体填充墙进行数值模拟研究,分析比较两种墙体在爆炸冲击作用下的动态响应和防护性能。结果表明:在同级爆炸荷载作用下,随着钢板厚度的增加,防爆墙体的刚度也随之增强,加速度峰值会不断提前;墙体瞬时速度最大值出现在0.1 ms前后,当钢板厚度小于10 mm时,受爆点中心速度大于58 m/s;当钢板厚度大于30 mm时,受爆点中心速度小于30 m/s。随着爆炸荷载的增加,防爆墙中心点的最大变形位移和稳定变形位移都会随之增加,加固后的钢板夹芯防爆砌体墙的瞬时位移随着钢板厚度的增加呈现减小的趋势。当钢板夹芯防爆墙的钢板厚度小于20 mm时,墙体的最大塑性位移大于0.015 m,当钢板厚度大于30 mm时,墙体的最大塑性位移小于0.008 m。由于夹芯钢板对墙体延性的提升,钢板夹芯砌体墙的损伤情况明显好于钢筋混凝土加固砌体墙。防爆墙的钢筋应变在爆炸冲击波的作用下瞬时拉压变形交替出现,其中心线随着爆炸荷载的增加和时间的推移呈上升趋势,防爆墙受爆中心点的钢筋拉压应变最大,钢板厚度的增加对于墙体边缘的钢筋拉压应变变化影响很小。加固后的钢板夹芯防爆砌体墙的抗爆性能受钢板厚度的影响,随着钢板厚度的增加,可以显著提升原砌体墙、混凝土加固砌体墙的抗爆性能。
Abstract:
Considering the improvement of anti-explosion performance of existing facilities such as dangerous chemicals warehouse and ammunition depot, a explosion-proof wall structure was established. Using the numerical simulation method, taking the unreinforced masonry infilled wall and the composite masonry blast wall based on steel plate concrete as the research objects, the dynamic response test of the masonry wall under explosive load was carried out using the dynamic nonlinear finite element analysis software ABAQUS/Explicit. In the model, masonry wall, cast-in-place concrete, TNT and sandwich steel plate were solid unit type, and the reinforcement mesh was beam unit type; The reinforcement mesh was embedded in the cast-in-place concrete, and the brickwork wall, cast-in-place concrete and sandwich steel plate were in surface-to-surface contact contact; In the contact properties, the penalty function was used, the friction coefficient is 0. 75, and the bond slip between blocks adopted exponential damage evolution constitutive law; The structural model used the full constraint type to constrain the bottom and top of the wall, and used the fine finite element to divide the grid, with the size of 0. 01 m. The dynamic response and protective performance of the two kinds of walls under the impact of explosion were analyzed and compared by numerical simulation. The results showed that under the same level of explosion load, with the increase of the thickness of the steel plate, the rigidity of the explosion-proof wall would also increase, and the peak acceleration would continue to advance; The maximum instantaneous velocity of the wall appeared around 0. 1 ms. When the thickness of the steel plate was less than 10 mm, the center velocity of the explosion point was greater than 58 m/s; When the thickness of the steel plate was greater than 30 mm, the central velocity of the explosion point was less than 30 m/s. With the increase of explosion load, the maximum deformation displacement and stable deformation displacement of the center point of the blast wall would increase. The instantaneous displacement of the reinforced steel sandwich blast wall would decrease with the increase of the thickness of the steel plate. When the steel plate thickness of the steel plate sandwich explosion-proof wall was less than 20 mm, the maximum plastic displacement of the wall was greater than 0. 015 m; when the thickness of the steel plate was greater than 30 mm, the maximum plastic displacement of the wall was less than 0. 008 m. Due to the improvement of wall ductility by sandwich steel plate, the damage of steel plate sandwich masonry wall was obviously better than that of reinforced concrete masonry wall. The steel bar strain of the blast wall appeared alternately under the instantaneous tension and compression deformation under the action of the blast wave, and the center line showed an upward trend with the increase of the blast load and the passage of time. The tensile and compression strain of the steel bar at the center of the blast wall was the largest, and the increase of the steel plate thickness had little effect on the tensile and compression strain of the steel bar at the wall edge. The anti-explosion performance of the reinforced steel sandwich explosion-proof masonry wall was affected by the thickness of the steel plate. With the increase of the thickness of the steel plate, the anti-explosion performance of the original masonry wall and the concrete reinforced masonry wall could be significantly improved.
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