The Experiment Research On The Treatment Of The Collapsible Foundation Of Karamay Airfield

Collapsible foundation generally belongs to the saline soil. When the salinity content in thefoundation soils reaches certain value, the characterization of body subsidence subjected to watersoaking is defined as foundation collapsibility. The aim of the foundation treatment to collapsiblesoils is to eliminate foundation collapsibility, upgrade the stability of the soils subjected to watersoaking and improve the bearing capacity.The mechanism and the mode of the collapsibility of saline soils, as well as the domestic andoverseas research state at present, are summarized. A great deal of experimental research andpractical experience are obtained in domestic and abroad. Based on these research achievements andexperience, the mechanism, scope of application and exiting problem of some methods treating thecollapsibility of saline soils, such as soak predissolving, dynamic consolidation, soak predissolvingand dynamic consolidation, soil replacement and bedding cushion, salinization method and pilefoundation, are discussed in the thesis.Although present the treatment technology and method of collapsible foundation have sometheoretic base, there are a good many deficiencies. Soak predissolving is firstly to make the salinemater in foundation soils fully dissolve and permeate to deeper soil layer with the gravity water orelevate to surface soils with the capillary water to eliminate saline matter so as to reach the goal ofdecreasing the salinity content, and then dynamic consolidation is implemented on the predissolvedfoundation soils so as to achieve the goal of increasing the compactness, improving strength andstability of the foundation soils. It is less witnessed that the soak predissolving and dynamic consolidationmethod is adopted to treat the collapsibility on clay saline soils, and therefore its mechanism,treatment effect and construction control should be researched and explored further.Combined with the experimental research project of foundation treatment to the collapsiblesoils at Karamay Airport, the experiment using the method of soak predissolving and dynamicconsolidation to treat the collapsibility of clay saline soils is done. The experimental results indicatethat the method of soak predissolving and dynamic consolidation is effective to treat the collapsiblefoundation soils at Kelamayi Airport. A great deal of outcomes and understandings of treating thecollapsibility of clay saline soils by the means of soak predissolving and dynamic consolidation toeliminate the collapsibility are obtained:The quantity of water used for predissolving is the key index for assuring the soaking effect,and will directly affects the cost of predissolving method. And it has relation with severalparameters, such as the type of soils, origin salinity content, mineralization of douching water, andatmospheric temperature at the time of douching.The mode of soaking and the exposing time are the primary index for construction timecontrol, so different modes of soaking should be adopted for soils layers with different permeability,such as clay and sand;proper exposing time can make the saline rise sufficiently through thecapillary action, and then removing a certain thickness of surface soils can decrease the salinitycontent in the foundation soils.Dynamic consolidation is the primary index for construction time and quality control, and it isfeasible that dynamic consolidation on the post-soaked soils is performed after a given interval time.Using proper compact energy, compact times and compact point layout can achieve the purpose offoundation treatment.Furthermore, the programs of construction control and their economic rationality are analyzed.It is considered that the program of construction control is reasonable and that the expenditure iseconomic, the purpose of experimental research is achieved.