沙漠风积沙上拔角取值研究OA

Deserts are commonly distributed in China,and spread foundations are widely used in overhead transmission line engineering in desert regions.Uplift cone angle of aeolian sand serves as a key parameter in determining the uplift bearing capacities of spread foundations when using the earth cone weight method.This paper compiled the results of 31 in-situ and 45 model tests on the uplift resistance of spread foundations in aeolian sand.The spread foundations included six structural types:cast-in-place rigid stepped foundations,guyed disc foundations,cast-in-place flexible column-plate foundations,prefabricated concrete plate-tube steel column foundations,prefabricated concrete plate-steel support foundations,and all-metal prefabricated plate-steel support foundations.The tests were conducted under two types of loading conditions:uplift and uplift-combined lateral force.Based on the uplift load-displacement curve characteristics of spread foundations,the criteria for determining the ultimate bearing capacity of uplift spread foundations were suggested,and the uplift cone angles of each test condition were correspondingly derived.Based on these results,corresponding uplift angles for aeolian sand foundations are inversely calculated.Through statistical analysis of uplift angles under all test conditions,a standard uplift cone angle αk=15° was recommended for aeolian sand in desert regions.This value comprehensively considered factors such as desert regional characteristics,spread foundation types and their structural forms,foundation geometric dimensions,foundation embedment characteristics of depth-to-width ratio,and lateral load effects,and which can serve as a basis for revisions of relevant standards.