An instrumented 1:70 scale model underground tunnel, located below a free water body, was subjected to explosions in centrifuge model tests. Utilising centrifuge scaling relations, each test at 70g modelled the effects of an explosion due to approximately 0.9 t of trinitrotoluene equivalent. The explosives were located at the ground surface, above the tunnel centreline. The effect of water level on the extent of damage was of primary interest in this study. Instrumentation in each test included pore-water pressure (PWP) transducers and strain gauges. PWP and strain measurements showed instantaneous increase due to the explosion, followed by gradual dissipation. The magnitude of peak pore pressure and strain increased with increase in water level. PWP ratios, calculated based on measured PWPs during the centrifuge tests, indicate that liquefaction occurred near the ground surface, close to the crown of the tunnel in all cases and at the bottom, near the endspan, only when the water level was high. The measured pore-pressure ratios and strains, induced due to the explosion, are useful in understanding the effects of explosion on an underground tunnel below a water body.

中文翻译：

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离心机试验中水下爆炸引起隧道附近孔隙压力的发展

位于自由水体下方的仪表 1:70 比例模型地下隧道在离心机模型测试中遭受爆炸。利用离心机比例关系，每次测试 70 g模拟了大约 0.9 吨三硝基甲苯当量引起的爆炸影响。炸药位于地表，隧道中心线以上。水位对损坏程度的影响是本研究的主要兴趣。每个测试中的仪器包括孔隙水压力 (PWP) 传感器和应变计。PWP 和应变测量显示由于爆炸而瞬间增加，然后逐渐消散。峰值孔隙压力和应变的大小随着水位的增加而增加。PWP 比率是根据离心试验期间测得的 PWP 计算得出的，表明液化发生在靠近地表的所有情况下，靠近隧道的冠部和底部，靠近端跨，只有当水位高时。