Contribution Of Extruded Polystyrene Board In Frost Heaving Prevention Of Irrigation Channel With Concrete Lining

Northern China is a monsoon climate,with large temperature difference between winter and summer.The irrigation channels with concrete lining in this area suffer from frost heaven,resulting in the damage in concrete lining.As a result,each year,a large amount of manpower,material resources and financial resources are required for the irrigation channel reparation and maintenance.And lots of precious water resource is wasted.In order to ensure the sustainable development of the agricultural irrigation in northern China,this current research is devoted to the contribution of XPS(eXtruded PolyStyrene board)in the frost heaving prevention of irrigation channel with concrete lining and to propose some useful engineering application suggestions.This work is one part of the key research and development project of Shandong Province,“The Investigation of Frost Heaving Damage in Irrigation Channel and the Engineering Prevention Measures”.The irrigation channel with concrete lining in Weishan irrigation district,Liaocheng,Shandong Province has been chosen as engineering practice background in our study.The contribution of XPS board on the frost heaving prevention in the chosen irrigation channel has been studied via both the laboratory tests and numerical simulations.The main research works and conclusions are as follows:1.The literature analysis is firstly presented.The state of art of scientific research on the frost heaving in irrigation channel,the current engineering prevention measurements are also discussed.2.The frost heaving tests are carried out in our laboratory with soils taking from Weishan irrigation district,which served as the foundation soil for the concrete lining in the irrigation channel.It is found that the soil is sensitive for the frost heaving.It is also found that the temperature drop rate has important influence on the frost heaving.3.By using ANSYS,the chosen irrigation channel in Weishan irrigation district has been analyzed via the numerical approach.Both the steady state and the transient state heatanalysis are conducted for the irrigation channel,in using the local observed weather information.The freezing depth and frost heaving with time are discussed.The contribution of XPS board is also analyzed and discussed.4.In average,each 0.01 m extruded polystyrene board can reduce the freezing depth of0.1433 m and the frost heaving of 0.0065 mm.However,as the thickness of the laminated XPS board increases,the reduces of freezing depth and the frost heaving are gradually slowed down.Therefore,it is necessary to select a suitable thickness of XPS board according to the actual working conditions of the irrigation channel.After careful comparisons,the thickness of 0.05 m has been chosen for the XPS board for the thermal isolation.5.The comparison between the numerical results and the laboratory tests and in-situ measurements demonstrate that the proposed numerical model and its results are reliable.