反拱水垫塘在上举力作用下底板块轴力的试验研究  

Experimental study on axial forces between slabs of inverted arch plunge cushion pool under action of uplift forces

作　　者：张春财[1,2] 孙建[1] 张金明[1] 杨丽萍[1] 刘艳丽[1] 

机构地区：[1]西安理工大学,西安710048 [2]长沙理工大学水沙科学与水灾害防治湖南省重点实验室,长沙410114

出　　处：《水力发电学报》2013年第2期168-174,共7页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金项目(50279040);陕西省国家重点学科建设项目;西安理工大学特色研究项目(215369);水沙科学及水灾害防治重点实验室开放基金项目(2013SS06)

摘　　要：以溪洛渡高拱坝和反拱水垫塘为参照,在高水头、大流量作用下,以反拱水垫塘在止水破坏、拱圈单底板块和九底板块锚固分别失效为代表工况,对拱圈底板块在上举力作用下的轴力进行试验研究。研究表明,拱圈底板块轴力产生和传递的机理是,底板块上举力诱导了底板块位移和锁定,锁定后相邻底板块产生了约束轴力,同时轴力又反过来向相邻底板块传递直至拱端。轴力沿程可分为冲击强振区和上下游强振区。在冲击强振区,底板块瞬时值较大,时均值小,脉动强度最大,拱圈底板能瞬时锁定形成瞬时拱;在上下游强振区,底板块瞬时值和时均值大,而脉动强度较小,拱圈底板块能长时间锁定形成局部拱。在三个强振区,底板块轴力的优势频率在小于0.2Hz的低频窄带。试验条件下拱圈底板块不发生强度破坏、共振破坏。反拱水垫塘运用时,应控制底板块位移、减少拱圈锁定底板块数,才能使轴力分布在合理范围。An experiment was conducted to study the axial forces on the bottom slabs under action of uplift forces for an inverted arch plunge pool that works under high water heads and large discharges similar to the Xiluodu high arch dam,considering two cases of failure in anchoring structure of a single slab and nine slabs on the arch ring.Results reveal the mechanism of axial forces generation and transmission,i.e.after the uplift forces induce shifting and locking of certain slabs,constraint axial forces are created on their adjacent slabs and these forces are transferred in turn to the next neighboring slabs,until to the arch abutments eventually.The distribution of such axial forces can be divided into a region of strong impacting vibrations and two regions of upriver and downriver strong vibrations.The former region is featured with small time-average axial forces,large instantaneous axial forces and strong slab vibrations,so the slabs is locked only in a short time,forming a instantaneous arch.But the latter regions are featured with large instantaneous and time-average axial forces and weaker slab vibrations,so the locked slabs can form a local arch for longer time.In all these three regions,the dominant frequencies of slab vibrations fall within a narrow range of low frequency below 0.2 Hz.Thus,when an inverted arch plunge pool is in operation,to control the magnitude of its axial forces within a suitable range,the radial displacement of its bottom slabs and the number of locked slabs should be reduced.

关 键 词：水力学 反拱水垫塘 轴力 试验研究 拱圈底板块 上举力 

分 类 号：TV635.3[水利工程—水利水电工程]