摘要
在理想的同步注浆条件和不计浆液性状变化影响的前提下,将盾尾后方管片受到的总上浮力分为随地层条件和隧道埋深而变化的广义动态上浮力以及由液态浆液包裹而产生的静态上浮力两部分,推导出这2种上浮力的计算公式。动态上浮力在盾尾后方一定距离范围内长期存在;基于盾尾空隙横断面内的浆液压力梯度的变化规律,给出静态上浮力的作用范围。根据管片的上浮模式,考虑管片环间的纵向约束作用,得出维持隧道抗浮稳定需要的浆液最小屈服强度表达式,明确了浆液屈服强度对隧道抗浮稳定具有决定性作用、围压对提高浆液屈服强度有积极的作用。
On the premises of ideal simultaneous backfill grouting, and without regard to the influences of the change of grout characteristics, the upward movements of segments in three-dimensional annular space at the rear of shield tail were researched. The upward buoyancy acted on segments was divided into two parts, namely, the generalized dynamic buoyancy changing with ground conditions and buried depth of tunnel, and the static buoyancy depending on surrounding liquid grout. The formulas of the two types of upward buoyancy were derived. The dynamic buoyancy existed for a long time within certain distance range at the rear of shield tail. The action range of static buoyancy was given based on the change law of the grout pressure gradient in the cross section of tail void. On the basis of the whole floating mode of the segments at the rear of shield tail, and considering the longitudinal constraints between segments, the ex- pression for the least yield strength of grout was obtained to maintain the anti floating stability of tunnel. The decisive role of the yield strength of grout on maintaining the anti-floating stability of tunnel was made clear, and the positive role of surrounding pressure on improving the yield strength of grout was also made clear.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2013年第1期59-66,共8页
China Railway Science
关键词
盾构隧道
同步注浆
盾尾空隙
上浮力
屈服强度
Shield tunnel
Simultaneous backfill grouting
Annular space at the rear of shield tail
Up-ward buoyancy
Yield strength
