考虑主槽移位的盾构隧道冲刷边界确定及管片优化

A Main-Channel-Shift-Considered and Scour-Border-Determined Optimized Design for a Shield-Cut Tunnel

河道主槽演化影响着流域范围内工程活动的环境边界。兰州地铁穿越黄河区间通过强透水、大水头、弱胶结巨厚砂卵层,依据水力和能量方程法推算百年水位和河道流量,继而推求主河槽移位条件下工程断面的最大冲刷线,以此明确隧道结构的应力及位移边界。最后,基于不同冲刷条件下管片的力学响应,对管片设计提出分区分段的设置原则,为穿越江河隧道的管片设计提供优化思路,并达到安全、经济设计目的。

The evolution of the main channel of a river plays an important role in affecting the environmental borders of engi- neering activities within the valley of the river. As the Lanzhou subway goes through the Yellow River drainage basin,it is faced with strong water permeability, great water head and the extra-deep poorly-glued grit seam, in which case the one-hundred-year water levels and the flow of the river have to be estimated according to the hydraulic and energy equations, upon the basis of which the maximum scour line of the engineering cross-section under the action of the shift of the main channel is further ob- tained so as to make clear the stress of the tunnel structure and the borders of the shift. Finally,according to the mechanical re- sponse of the lining under different scour conditions, the providing principle for the design of different-strength lining sections is proposed section by section. The research may provide a new thinking way for optimizing the lining design for the tunnel go- ing through rivers, with the aims of safety and economy in design realized.