【作者】 朱浩；

【导师】 王永胜； 马强；

【作者基本信息】 兰州理工大学 ， 建筑与土木工程（专业学位）， 2022， 硕士

【摘要】 由于泥石流发生过程随机性强,对防治结构的作用不确定性高,如果按照传统最不利情况设计,将会造成较大的工程浪费。因此,运用随机理论来分析泥石流对防治结构的作用,进利用可靠性理论进行研究与设计是十分必要的。为了大规模推广与应用新型地锚扶壁式泥石流格栅坝(以下简称新型泥石流格栅坝),本文在结构可靠度基本理论的基础上,开展了室内泥石流多点冲击试验与结构体系可靠度研究。主要内容与研究成果如下:(1)根据横梁和拉锚体系在块石冲击作用下的破坏模式,建立块石冲击下横梁抗弯、抗剪和锚墩抗拔力、拉索承载力极限状态方程,利用结构可靠度的基本理论及计算方法计算横梁和拉锚体系各失效模式的可靠度指标。(2)通过体系可靠度失效概率的点估计计算方法,建立新型泥石流格栅坝结构体系可靠度指标方程。结果表明,在泥石流块石冲击作用下,新型泥石流格栅坝横梁最先受到破坏;块石冲击下截面高度、宽度和混凝土强度的增加提高了坝体体系可靠度指标,其中截面高度对体系可靠度指标的影响最大。但这种增幅随着原有截面高度、宽度和混凝土强度的增加呈现减小的趋势。块石半径、速度和作用位置是影响体系可靠度指标的直接因素,冲击点位置对体系可靠度指标的影响随着块石半径的增大而变大。(3)制作两个新型泥石流格栅坝试验模型,用钢球代替泥石流中的块石,设置多点和单点冲击工况。验证了新型泥石流格栅坝横梁最先受到破坏;借助自助抽样法对所采集数据进行均值和标准差计算,并将数值带入公式计算了对应格栅坝的可靠度指标。更多还原

【Abstract】 Due to the strong randomness in the occurrence process of debris flow,the uncertainty of the effect on the prevention and control structure is high.If the design is based on the traditional worst case,it will cause a large amount of engineering waste.Therefore,it is very necessary to use the random theory to analyze the effect of debris flow on the prevention and control structure,and to use the reliability theory to conduct research and design.In order to popularize and apply the new type of ground-anchored buttressed debris flow grille-dam(hereinafter referred to as the new type of debris flow grille-dam)on a large scale,on the basis of the basic theory of structural reliability,this paper carried out indoor debris flow multi-point impact test and structural system reliability research.The main contents and research results are as follows:(1)According to the failure mode of the beam and the tension anchor system under the impact of the block rock,the limit state equations of the bending resistance,shear resistance and anchor pier pullout resistance and the bearing capacity of the tension anchor system under the block rock impact are established,and the basic theory of structural reliability is used,and the calculation method is used to calculate the reliability index of each failure mode of the beam and the tension anchor system.(2)Through the point estimation calculation method of system reliability failure probability,the reliability index equation of the new debris flow grille-dam structure system is established.The results show that under the impact of debris flow,the beams of the new type of debris flow grille-dam are first damaged;the increase of section height,width and concrete strength under the impact of debris flow improves the reliability index of the dam system,the index has the greatest impact.But this increase shows a decreasing trend with the increase of the original section height,width and concrete strength.The rock radius,speed and action position are the direct factors that affect the reliability index of the system,the influence of the impact point position on the reliability index of the system increases with the increase of the radius of the rock.(3)Two new types of debris flow grille-dam test models were made,and steel balls were used to replace the boulders in the debris flow,and multi-point and single-point impact conditions were set.It is verified that the beams of the new type of debris flow grille-dam are damaged first;the mean and standard deviation of the collected data are calculated by means of the self-service sampling method,and the values are brought into the formula to calculate the reliability index of the corresponding grille-dam.更多还原