Exothermic process of cast-in-place pile foundation and its thermal agitation of the frozen ground under a long dry bridge on the Qinghai-Tibet Railway

A number of dry bridges have been built to substitute for the roadbed on the Qinghai-Tibet Railway,China.The aim of this study was to investigate the exothermic process of cast-in-place (CIP) pile foundation of a dry bridge and its harm to the stability of nearby frozen ground.We present 3D heat conduction functions of a concrete pile and of frozen ground with related boundaries.Our analysis is based on the theory of heat conduction and the exponent law describing the adiabatic temperature rise caused by hydration heat.Results under continuous and initial conditions were combined to establish a finite element model of a CIP pile-frozen ground system for a dry bridge under actual field conditions in cold regions.Numerical results indicated that the process could effectively simulate the exothermic process of CIP pile foundation.Thermal disturbance to frozen ground under a long dry bridge caused by the casting temperature and hydration heat of CIP piles was substantial and long-lasting.The simulated thermal analysis results agreed with field measurements and some significant rules relating to the problem were deduced and conclusions reached.

Nonlinear Discrete Inequality in Two Variables with Delay and Its Application

Delay discrete integral inequalities with n nonlinear terms in two variables are discussed, which generalize some existing results and can be used as powerful tools in the analysis of certain partial difference equations. An application example is also given to show boundedness of solutions of a difference equation.

The incentive and coordination strategy of sustainable construction supply chain based on robust optimisation

This paper considers the incentive and coordination problem of the construction supply chain consisting of the owner,general contractor,subcontractors and suppliers based on the sustainable development goals under uncertain environment.Firstly,according to the general contract management pattern and the relationships among those participants,we establish an uncertain bi-level nonlinear model in which the owner set the proper intensities to minimise the total cost at first while the general contractor decides its alternative and the limits to subcontractors correspondingly.Then,we convert the primal model into a deterministic bi-level nonlinear programming model based on the concept of relative robustness.Next,a solution procedure combing interactive fuzzy technique and genetic algorithm is designed.Finally,the validity of the model is verified by a numerical example.Our paper provides a method to optimise the construction project management from the perspective of supply chain under the requirement of sustainable development.