随着大型矿用卡车在我国露天煤矿的广泛应用，建立中间搭桥运输系统逐渐成为一种有效的节省运输费用方法。为了减少露天矿中间搭桥运输系统运输距离，优化该系统的重要参数——桥面高度，通过分析搭桥运输系统和双环运输系统卡车运输距离的变化规律，以坑底水平为基准，考虑不同水平到桥面折返距离的动态变化，依据运输功最小原则，得出不同工作面剥离物料的动态分界位置，并在此基础上建立内排运输功计算模型，进而得出运输费用，该模型扩大了搭桥运输系统的服务范围；为了减少拆桥二次剥离量，实现拆除桥体经济合理，从桥体搭接位置处的形状、组成桥体的成分及二次剥离过程3个方面进行分析，提出了经济合理二次剥采比的概念及计算方法，得出了经济上允许的最大二次剥离量与采矿量之比，从而确定最大二次剥离深度，进一步建立拆桥费用模型；根据收益最大原则，确定搭桥运输系统的桥体最佳高度，使近水平露天矿中间搭桥系统充分发挥作用，具有一定的普适价值。针对宝日希勒露天煤矿开采现状，通过模型计算得出随着桥体高度的增加，桥体服务范围整体提高，且服务范围内的台阶数量呈现由少变多再变少的规律；就某一台阶节省的运输费用，随着该台阶高度与桥体高差的增大而减小；不同桥体节省费用的最大值随桥体高度的增加而增大，最终得出最佳桥体高度为55 m，一次搭桥循环时间内，可增加收益约2 901.5万元。

With the wide application of large mining trucks in open-pit mines in China,the establishment of an pit-middle bridge transportation system has gradually become an effective method of saving transportation costs. In order to give full play to the role of the pit-middle bridge transportation system in open-pit mines in saving transportation distance,the important parameter of the system-bridge deck height is optimized. This paper analyzes the change law of the truck transportation distance between the pit-middle bridge transportation system and the double-loop transportation system,takes the level of the pit as the benchmark,and considers the dynamic changes of the return distance from different levels to the bridge deck. According to the principle of minimum transportation power,the results of stripping materials at different working faces dynamic demarcation position,and on this basis,establish a calculation model of internal discharge transport work,and then obtain transportation costs. This model expands the service scope of the pit-middle bridge transportation system;in order to reduce the amount of secondary stripping of the bridge and realize the economical and reasonable removal of the bridge,the shape of the bridge at the overlapping position,the composition of the bridge and the secondary stripping process were analyzed,and an economically reasonable secondary was proposed. The concept and calculation method of stripping ratio,the ratio of the economically allowable maximum secondary stripping volume to the mining volume was obtained,so as to determine the maximum secondary stripping depth,and further establish the bridge demolition cost model;according to the principle of maximizing profit,the optimal height of the bridge body of the pit-middle bridge system is determined,so that the pit-middle bridge system of the near horizontal open pit mine can fully play its role and has certain universal value. Aiming at the current situation of Baorixile open-pit coal mining,it is found through model calculation that as the height of the bridge increases,the overall service range of the bridge increases,and the number of steps within the service range shows a law of changing from less to more to less;the transportation cost saved by a certain step decreases as the height difference between the step height and the bridge body increases;the maximum cost savings of different bridges increases with the increase of the height of the bridges. In the end,the best bridge height is 55 m,and the bridge can be increased by about 29.015 million yuan in one bypass cycle. 

0 引言

1 搭桥运输系统模型建立

   1.1 运输功模型

   1.2 搭桥费用模型

2 实例分析

   2.1 宝日希勒露天煤矿生产条件

   2.2 宝日希勒露天煤矿搭桥高度优化

3 结论