无粘结环锚预应力衬砌锚具槽布置方式对比研究

无粘结环锚预应力衬砌锚具槽是整个预应力衬砌受力的关键部位,其位置的选择对于整个预应力衬砌受力和安全而言至关重要。结合引松供水工程有压输水隧洞无粘结预应力衬砌结构,采用等效荷载法和实体建模相结合的方法进行Flac3D三维建模,对锚具槽单排和双排布置时的衬砌关键部位受力情况进行了分析。计算结果表明:(1)无粘结环锚预应力衬砌的下半环因锚具槽的影响,会存在局部预应力缺失和分布不均,而单排锚具槽布置能减小衬砌预应力的不均匀性。(2)锚具槽及附近区域是预应力衬砌的薄弱区,衬砌拉应力区主要分布在锚具槽环向的临空面附近,衬砌受压最大区域分布在相邻锚具槽之间。(3)双排锚具槽布置型式抗超载能力优于单排锚具槽布置型式。

Comparative study on layout patterns of anchorage slots for pre-stressed lining with unbonded circular anchored tendons

The slots of pre-stressed lining anchorage with unbonded circular anchored tendons are the key forced parts for entire pre-stressed lining， and then the selection of their locations is quite important for the forced status and safety of entire pre-stressed lining. Combined with the unbounded pre-stressed lining structure of the pressure water conveyance tunnel for Songhuajiang River Diversion Water Supply Project， the forced statuses of the key parts of the lining with single-row layout and double-row layout of anchorage slots are analyzed with Flac3D modeling carried out by combining equivalent load method with solid modeling method. The calculation result shows that: （1） the absence and ununiform distribution of the local pre-stress are there at the lower half-ring of the pre-stressed lining with unbonded circular anchored tendons due to the influence from anchorage slot， whereas， the ununiformity of the lining pre-stress can be reduced by the single-row layout of the anchorage slots； （2） both the anchorage slots and the areas near them are the weak locations for the pre-stressed lining and the lining tensile stress areas are mainly distributed near the circular free face of the anchorage slot， while the maximum forced areas of lining are distributed in between adjacent anchorage slots； （3） the anti-overload capacity of the double-row layout of anchorage slots is better than that of the single-row layout of anchorage slots.