Experimental study on the static behavior of railway corrugated-steel pipe culvert with thin soil cover
Currently,experimental studies on the mechanical behavior of corrugated-steel pipe culverts considering railway load characteristics are rare.To support the application of corrugated-steel pipe culverts in railway engineering,experimental study is conducted to investigate the mechanical behavior of railway corrugated-steel pipe culverts.The structural configuration of railway culvert is experimentally simulated and static loading tests on railway corrugated-steel pipe culverts are conducted.Thin soil cover is adopted for corrugated-steel pipe culverts to focus on the mechanical response of corrugated-steel pipe culverts under railway live load.The results show that,there was no culvert-soil detachment with soil covers of 0.6 m sand+0.3 m gravel and 0.3 m sand+0.3 m gravel,which means soil-structure interaction is guaranteed;but local stress state of combined circumferential tension and bending was experimentally observed.As the soil cover depth increases,the culvert stress under dead load plus live load first decreases and then increases,and the inflection point in this paper is about 2～3 meters depth;from the perspective of culvert stress,there exists an optimal soil cover depth.As the load moves away from the culvert,the maximum culvert stress position shifts from the culvert top to the load side 45°;when the load position is 0.3 m away from the culvert top,the culvert stresses reach the maximum,and thus eccentric loads should be considered in design.As the compaction degree(elastic modulus)of sand around culvert increases,the maximum culvert stress slightly decreases,while the culvert deflection obviously decreases;the reason should be that the sand around the culvert enters a yielding state locally,so the maximum culvert stress is slightly affected while the overall response at deflection is obviously affected.When the minimum soil cover depth specified in relevant specifications in highway field is adopted for railway corrugated-steel pipe culverts,the culvert and soil will not detach,and thus soil-structure interaction is guaranteed;however,the railway load transfer method of track-sleeper-bed tend to cause a local circumferential tension-bending stress state in pipe culverts,so it is recommended to apply a larger soil cover depth.
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