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一、引言我国大规模的水利建设中,设计大头坝和宽缝重力坝的极多,如磨子潭、新丰江、桓仁、湖南镇、拓溪、万家寨,丹江口,刘家峡、三峡、五强溪等。据笔者所知,目前对大头坝及宽缝重力坝的应力分析,多采用几何法[1],或引用磨子潭工程采用的假定σ_x 直线分布的计算法[2]及巫必灵等提供的不考虑宽缝边界的渐变(事实上渐变长度与上下游非宽缝部份的长度相近)亦假定σ_x 为直线分布的方法[3]。以上三种方法,均基于重力法的假定——垂直应力在上下游方向为直线分布,未考虑基础变形的影响。前者是重力法的一种数值解法,计算工程量极大;第二种方法的假定与突际情况相差过远(可参阅附录中的算例),误差较多;第三种方法误差亦多,且不适用于大头坝。正如三峡大坝设计纲要中所提:“磨子潭用的等值断面的方法不尽合理……对本问题目前尚不很明确,即究竟应该如何修正计算公式”。说明目前设计中,需要研究一种比较精确而又切实可行(工作量不大)的计算方法。
I. INTRODUCTION In China’s large-scale water conservancy construction, a great number of large-headed dam and wide-gap gravity dam are designed, such as Mozititan, Xinfengjiang, Huanren, Hunan, Tuoxi, Wanjiazhai, Danjiangkou, Liujiaxia, , Five strong Creek and so on. As far as I know, at present, the stress analysis of Dadouba and wide slit gravity dams mostly adopts the method of geometry [1], or the calculation of the straight line distribution of assumed σ_x used in the Mudisitan project [2] and Wu Biling Considering the gradual change of the width of the gap (in fact, the length of the transition is similar to the length of the non-wide-gap portions), it is also assumed that σ_x is a straight-line distribution [3]. The above three methods are based on the assumption of gravity method that the vertical stress is linear in the upstream and downstream directions without considering the influence of the foundation deformation. The former is a numerical method of gravity method, the calculation of the project volume is extremely large; the second method of assumptions and the sudden situation is far away (see the appendix in the example), the error is more; the third method error , And does not apply to the bulk dam. As mentioned in the Outline for the Design of the Three Gorges Dam: “The method of equivalent section for Mozi Lake is not reasonable ... It is not clear to this question that how to correct the formula.” Description of the current design, the need to study a more accurate and practical (workload is not) calculation.