扬压力作用下反拱水垫塘缝隙动水压力研究

以国内某高坝工程为参照,对水垫塘排水和底板锚固措施都失效后,底板缝隙动水压力随扬压力、底板缝宽以及不同止水破坏程度这3个关键因素的变化规律进行了理论分析和试验研究。研究表明,止水正常时,由于底板表面动水压力脉动、底板振动,使缝隙动水压力大于扬压力;止水破坏后在小扬压力范围内,缝隙动水压力增大,但增幅随扬压力增大而减小、也随底板缝宽增加、或止水破坏程度增加而减小;止水破坏后在大扬压力范围,缝隙动水压力减小,但减幅随扬压力增大而增大,也随底板缝宽增加、或止水破坏程度增加而减小。分析了水工规范中底板块安全系数的不妥之处,建议用缝隙动水压力代替扬压力准确计算底板块安全系数。工程中应尽可能做好排水措施,确保水垫塘排水设施正常运行。

Research on Hydrodynamic Pressure Spreading in the Base Gap of the Inverted Arch Plunge Cushion Pool by the Uplift Pressure

By referring to a high dam project under construction,the experimental investigation and theoretical analysis on the variation of hydrodynamic pressure spreading in the base gap with uplift pressure,widths of the contraction joints between slabs and varied destructive degrees of water seal installation were carried out by considering that any water seal installation between slabs and anchoring on them were all out of function.The study results showed that hydrodynamic pressure spreading in the base gap is larger than uplift pressure when water seal installation is normal.When water sealing is destroyed,within the smaller uplift pressure range hydrodynamic pressure spreading in the base gap increases,but the growth is lower with increase of uplift pressure,and lower with the increase of widths of the contraction joints between slabs and destructive degrees of water seal installation;within the larger uplift pressure range,hydrodynamic pressure spreading in the base gap decreases,but the reduction is higher with increase of uplift pressure,and lower with the increase of widths of the contraction joints between slabs and destructive degrees of water seal installation.Unreasonable point of the slab safety factor calculated by hydraulic design specification was analyzed,and uplift pressure was proposed to replace by hydrodynamic pressure spreading in the base gap through analyzing safety factor of slabs in the specification.Drainage measures should be done well in order to ensure normal operation of plunge pool’s drainage system.