Temporary Haul Road Design and Earthmoving Operation Planning on Rough Grading Projects: Integrated Optimization Approach

  • Author / Creator
  • Site rough-grading operations entail massive earthworks and are critical to plan and control large-scale land development projects and industrial construction projects. The material haulage cost typically accounts for around 30% of the total cost of the entire rough grading project. To improve hauling efficiency and save earthmoving operation cost, the common practice is to empirically construct limited lengths of temporary haul road (i.e. gravel surfaced high grade haul road, rough-ground low grade haul road) to handle the bulk of earthmoving jobs. In current practice, earthmoving jobs are generally planned based on cut and fill requirements prior to haul road layout design. However, the earthmoving operations and temporary haul road layout should be planned as a holistic system, because the two planning tasks are highly intertwined with each other (i.e. high grade haul roads are more expensive to build, but less expensive to operate while low grade haul roads are less expensive to build, but more expensive to operate). This separation introduces research opportunity as well as proposes challenges in planning earthmoving operations and temporary haul road layout design in an integrative fashion. This thesis applied existing scientific knowledge in both mathematical programming and computer science to address a practical problem in civil engineering by providing an integrated optimization framework that is capable to provide field planners with cost-effective solutions, verified in simulated realistic environment and ready for immediate implementation to guide earthworks planning practice. In particular, this thesis develops a complete package of applied science in construction engineering and management (i.e. apply existing scientific knowledge to develop practical applications in construction, and verify the solution generated by the science being applied in practical settings), including three parts: Part I applied latest advances in mathematical programming and computer science to develop an integrated optimization approach to simultaneously generate earthmoving operation planning and temporary haul road layout design resulting in the minimum cost. This includes mathematical modelling of the construction site, problem formulation, and algorithms devising. In particular, this thesis proposes a Cutting Plane Method based Mixed-integer Linear Programming (C-MILP) approach to optimize the temporary haul road layout design and generate earthmoving operation plans analytically by considering field constraints. The proposed method is capable to automatically produce the optimum solution in terms of minimizing the total earthmoving cost of a site grading project (i.e. a combined cost consisting of earthmoving crew cost, haul road construction and removal cost, and road maintenance cost). Part II devises an MILP based post-optimization sensitivity analysis approach to identify optimization model input parameter stability regions with the intention to provide the decision makers with enhanced confidence of the proposed mathematical model and insight in the optimum solution for possible practical application. This includes formalizing sensitivity analysis model, proposing a one-at-a-time (OAT) method, and designing algorithms. To be specific, this thesis firstly proposes a generic MILP sensitivity analysis model. Next, a one-dimensional line search approach is devised to find the boundaries of a stability region on each input parameter of the MILP optimization model, within which the optimum solution can be retained irrespective of the change to the input value. Part III develops an earthmoving operation analysis tool to facilitate validating the optimum solution resulting from applying science in math and computer science. Since abstraction and implicitness of analytical methods present the common hurdles to effective solution communication and interpretation, computer simulation is adopted to bridge the gap between analytical methods and implementation in reality. In this thesis, an Earthmoving Operation Analysis Platform (EOAP) tool has been prototyped to identify crew configuration and to evaluate earthmoving crew operation cost by computer simulation, automating the evaluation of simulation scenarios and facilitating the comparison of different solutions. The proposed approach was applied in a case study based on a real-world site grading project in Northern Alberta, Canada. The effectiveness of the proposed methodology was demonstrated in terms of generating optimum layout design and operation plan. The research deliverables have catered to the needs of earthworks contractors for enhancing current practices of planning site grading projects. The decision-makers are capable of taking advantage of the research for field productivity improvement and budget control purposes.

  • Subjects / Keywords
  • Graduation date
    Fall 2018
  • Type of Item
  • Degree
    Doctor of Philosophy
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