Optimization Model for Earth-Rock Allocation System in Large-Scale Hydraulic Engineering and Application in Shuibuya Project
Much importance is attached to the earth-rock allocation problem in the construction of many large-scale hydraulic engineering. Based on systemic view, the paper analyses the composition of the system and mutual relations among the elements. According to the analysis work, a linear programming model is constituted to optimize the operation of earth-rock allocation system to minimize the cost of the system. And the optimization model is put into operation in Shuibuya project in China. The calculating results by the model are economical and feasible in project construction
Further development of integer programming in earthwork optimization
The objective of existing linear programming methods of earthwork-system optimization in road construction has been either minimizing the cost or maximizing profit, generally without considering the project duration. This paper develops a linear programming model incorporating the project duration. The model attempts to optimize a comprehensive earthmoving system in road construction by comparing alternative fleets (from available fleets) to provide an optimum material distribution and appropriate plant fleets to complete a project within the specified time. The situations where different degrees of compaction, availability of various soil strata at cut sections and borrow pits, and selection of borrow/disposal sites are also incorporated. Among the possible extensions, equipment sharing between fleets and sequence of operations present at cut and fill sections are examined. The validity of the model is demonstrated by applying it to a numerical example, providing additional tools to the management such as the minimum project-completion time, the cheapest project cost and corresponding duration achievable with available resources.
Selection of roadway grades that minimize earthwork cost using linear programming
Abstract Roadway grades are normally established to satisfy the geometric specifications of the road. Once the grades are established, the earthwork allocations that minimize the cost are determined. This paper presents a model that links these two activities. The model selects the roadway grades that minimize the cost of earthwork and satisfy the geometric specifications. The geometric specifications pertain to the elements of the vertical alignment, elevation of grade line at specified stations, horizontal and vertical alignment relations, and type of vertical curve. The model enumerates all technically feasible grades and solves the linear programming problem to minimize earthwork allocation cost for those grade alternatives that satisfy borrow pit and landfill capacity constraints. The model incorporates important earthwork details and guarantees obtaining the global minimum earthwork cost. Application of the model is illustrated by a numerical example and model extensions to accomodate other design and construction aspects are presented.