土拱效应下的挂板式斜插桩板墙模型试验研究

Study on the Model Test of Hanging Plate Type Inclined Pile Wall under Soil Arching Effect

以新型的挂板式斜插桩板墙为研究对象进行室内模型试验研究,通过1∶20的相似理论来模拟实际工程中截面为1.5 m X2.0 m,悬臂段高为15 m的原型斜插桩板墙。模型板长分250 mm、300 mm、350 mm、400 mm、450 mm 5组,用来模拟实际桩间净距为5 m、6 m、7 m、8 m、9 m 5种工况,结合试验数据具体从桩板后土压力的分布状况;土拱效应强度、位置随桩间净距的变化、土拱强度随深度的变化及结构受力状况随桩间净距的变化等几方面对模型试验进行具体分析。随桩间净距的增大:模型桩、板后土压力均呈现增大趋势,当桩间净距小于300 mm时,回收位置较深;土拱强度减弱速度逐渐加快,当桩间净距小于300 mm时减弱较慢;土拱的位置即拱高逐渐增大,但其拱高位置整体处于约1/2桩间净距处;模型桩的结构受力也不断增大,悬臂段1/3范围以下开始,受力差距逐渐加大;斜插板轴力增大且随悬臂段的增加呈先迅速增加再减小趋势。

The new type of slanting pile plate wall with hanging plate was taken as the research object for indoor model test research,by using the similarity theory of 1∶20.The section in practical engineering is 1.5 m×2.0 m and the cantilever segment height is 15 m.The model board can be divided into five groups:250 mm,300 mm,350 mm,400 mm and 450 mm.It is used to simulate the actual five working conditions with the net spacing between piles being5 m,6 m,7 m,8 m and 9 m.The distribution of soil pressure on the pile plate was analyzed based on the test data.The model test was specifically analyzed in terms of the soil arch effect strength,the position change with the net distance between piles,the soil arch strength change with the depth,and the structure stress status change with the net distance between piles.As the net distance between piles increases:the soil pressure of model piles and plates all showed an increasing trend,when the net distance between piles was less than 300 mm,the recovery position was deeper.The strength of soil arch gradually increased,and decreased slowly when the net distance between piles was less than 300 mm.The position of soil arch,that is,the arch height gradually increased,but the overall position of the arch height was about 1/2 of the net distance between piles.The stress on the model pile structure is also increasing,and the difference of force is gradually increasing when the cantilever is less than 1/3 of the range.The axial force of the inclined insert plate increases rapidly first and then decreases with the increase of the cantilever segment.