近接基坑电力隧道开裂原因及整治技术

石家庄市石中一二线（16#-北道岔站）电缆隧道与阿尔卡迪亚三期商业综合体基坑工程近接，在基坑施工过程中隧道结构出现了开裂现象。采用无损检测、强度试验和数值模拟等手段，对隧道开裂原因进行了分析和探讨，并针对工程特点提出了隧道洞内套拱结合洞周地层注浆的综合治理方案。分析结果表明：在基坑施工过程中，原有隧道结构的安全性已不能满足要求，隧道洞内套拱结合洞周地层注浆的方案，能够保证后续施工和使用安全。

Experimental Research on Dynamic Response of Railway Steel-concrete Composite Beam Bridges

For further research of the dynamic response of steel-concrete composite beams, two groups of test beams were designed with the shear connection degree as parameter and dynamic tests carried out separately when the model trains passed through the test beams with different speed and different weight. The time-history curve of the vertical deflection crete slab at end support were and acceleration at the mid-span, and the slip between the steel girder and con- measured. The test results show that, the vertical deflection at mid-span and the slip at end support both enlarge with the increase of model train＇ s speed, but don＇ t express linear change law ; with the decrease of the shear connection degree, the beam＇ s stiffness reduces, but the dynamic coefficient in- creases; with the increase of the model train~ speed and weight, the dynamic coefficient has an upward tenden- cy.