密云水库走马庄隧洞加固方案施工导流方式分析

Analysis on construction diversion for strengthening of Zoumazhuang Tunnel of Miyun Reservoir

密云水库走马庄隧洞存在诸多安全隐患,需全面加固,而拆除重建隧洞进水塔面临着13 m深库水等不利的导流条件。在工程设计中,首先以比选围堰形式为基础,将拆除重建隧洞进水塔方案予以否定;随后,提出水下封堵止水方式,为避开深水围堰难题提供参考方案;最后,打破固有设计思路,在下游新建进水塔替代原进水塔,仅需利用原进水闸挡水进行施工。本设计方案在保证隧洞基本功能的基础上,保证相对合理的工程投资。

As so many potential safety hazards are there in Zoumazhuang Tunnel of Miyun Reservoir, an overall strengthening is then necessary. However, the unfavorable water diversion condition, such as the reservoir depth of 13m, etc. , is to be faced by dismantling and reconstructing the intake-tower therein. In the engineering design, the type comparison for the cofferdam is laid as the basis to negate the scheme of dismantling and reconstructing the intake-tower. Subsequently, the mode of the underwater plugging and sealing is put forward, so as to provide a reference scheme for avoiding the problem from the construction of a deep- water cofferdam. Finally, the inherent design concept is broken up, i.e. replacing the function of the original intake-tower with an intake-tower newly built at the downstream of it ; which only needs to retain water with the original intake gate for the construction. In this way, the basic function of the tunnel is realized, while the relative reasonability of the project investment is ensured as well, thus the design is better accomplished.