铁路路基端承桩施工问题探讨

Discussion on Construction Problem of the End Bearing Pile of Railway Roadbed

研究目的:铁路路基端承桩施工中经常出现桩与基岩面接触不好,端承力不够,接触面处易形成土体沉渣,容易造成地基不稳。通过采取相应检测方法和相应施工设备,使铁路路基端承桩底沉渣厚度不应大于50 mm,使桩端接触良好,提高施工质量,满足规范要求。研究结论:(1)以钻芯灌注桩的混凝土有效桩深为依据,对其桩做反射波法检测,可得出反射波曲线桩底呈正向特征,并可从反射波曲线中计算出反射波的速度值;(2)以上述速度值为参数,可用于被反射波法检测确定的桩深度;(3)取反射波法检测确定的桩深度与机械施工时的施工桩深度进行比较,若施工桩深度大于反射波法检测确定的桩深度,其差值为桩底沉渣厚度;(4)一个检验批次应不少于三个钻探孔的桩底沉渣厚度验证,沉渣厚度超过规范要求端承桩应返工处理;(5)端承桩的施工一定选取满足端承条件的端承机械设备,其端承桩施工设备不仅可用于端承桩施工,也可用于摩擦桩施工,但摩擦桩施工设备不可用于端承桩施工。

Research purposes： In railway roadbed construction of the end bearing pile, it often appears these phenomenons,for example,bedrock surface contact is bad,bedrock surface contact is bad,the bearing is not enough,the interface is easy to form at the soil sediment,easy to cause instability of foundation. By adopting the corresponding detection methods and the corresponding construction equipment,the railway subgrade end bearing pile bottom sediment thickness should not be greater than 50 mm,make the pile end contact good,improve the quality of construction,meet the specification requirements. Research conclusions：（ 1） First of all to core piles of concrete pile deeply effective basis for its pile do the reflection wave method to detect,it is concluded that pile bottom reflection wave curve positively to the characteristics,and from the reflection wave curve calculation in reflection wave velocity value.（ 2） The above speed value for parameters is used to detect certain pile depth by the reflection wave method.（ 3） Take the reflection wave method to detect certain pile depth and mechanical construction construction pile depth,if construction pile depth is greater than the reflection wave method to detect certain pile depth,the difference value is pile bottom sediment thickness.（ 4） A test batch should be not less than three drilling hole pile bottom sediment thickness verification,when sediment thickness more than standardrequirement end bearing pile should rework processing.（ 5） The end bearing pile construction must selecte the end bearing mechanical equipment which meets end bearing conditions,the bearing pile construction equipment can not only be used for end bearing pile construction,also can be used for friction pile construction,but the friction pile construction equipment is not used for end bearing pile construction.