新型预应力混凝土衬砌压力隧洞技术及其有限元分析

本文提出了一新型预应力混凝土衬砌压力隧洞技术,即:在厚壁圆筒承受内外水压力时,利用围岩的抗力作用,采用外加预应力法,在围岩和衬砌混凝土之间安装一种圆环形扁千斤顶设备——用薄钢板制成的中空圆环形压力囊,并根据需要利用水或水泥浆通过有限的径向位移对隧洞衬砌混凝土层外部人为地施加某一数值与分布的均布压应力,用以部分或全部抵消内水压力所产生的拉应力。其优点是不仅省去了预应力钢筋,而且施工简便、经济合理。还利用三维有限元法,分析了在隧洞衬砌混凝土外层间隔施加预应力时衬砌混凝土中应力的变化。计算结果表明,该技术是可行的,效果十分明显,可应用于实际工程。

Finite element analysis on a new technology for pressure tunnel with pre-stressed concrete lining

A new technology for the pressure tunnel with pre-stressed concrete lining is put forward herein； i.e. when thick-walled cylinder is under the internal and external water pressures，a circular-flat jacking device——a kind of hollow-circular pressure bladder is arranged between the surrounding rock and the lining concrete，and then the uniform compressive stress with a certain value and distribution range is factitiously applied to the outside of the concrete lining of the tunnel with water or cement mortar through the limited radial displacement according to the need concerned，so as to partially or wholly counteract the tensile stress caused by the internal water pressure. The merit of this technology is that not only the pre-stressed reinforcement is omitted，but the construction is also convenient，economic and reasonable. Furthermore，the stress change in the lining concrete during applying pre-stress to the space outside of the tunnel lining concrete is analyzed with 3D finite element method. The calculation result shows that this technology is feasible with a remarkable effect，and then can be applied to the actual project.