注浆微型钢管桩原体试验研究

Research on in-suit test of grouting micro-steel-pipe pile

针对一种新型的注浆微型钢管桩(试验桩)开展了现场原体试验,引入动测法对桩完整性进行了测试,开展了竖向抗压承载力试验研究。得出以下结论:注浆微型钢管桩(工程桩)完整性可采用低应变动测检测;当难以确定桩长,可按文中提出的式(1)对其波速进行计算,结合理论计算波速对桩长以及缺陷位置进行判定,有利于提高低应变动测结果的准确性。注浆微型钢管桩极限承载力取值,当建构(筑)物对地基沉降要求较高时,建议按Terzaghi法取值;当建构(筑)物对地基沉降要求一般时,建议参照文中规范取值。

In this paper,in-suit test of a new grouting micro-steel-pipe pile was carried out,with the dynamic testing methods for structural integrity of pile shaft being introduced and applied,and in-suit vertical static load test being implemented.Following conclusions are drawn:The pile integrity of grouting micro-steel-pipe piles can be checked by low strain dynamic testing;When difficulty to determine the length of the pile,the velocity of the wave can be calculated according to the formula(1)proposed in this paper,and with the theoretic calculated velocity value,we can judge the length of the pile and the position of the defect,which is beneficial to the improvement of the accuracy of the low strain measurement results.It is better to calculate the value of the ultimate bearing capacity of the grouting micro-steel-pipe piles with the Terzaghi method if the foundation settlements of the building need to be strictly controlled,and calculate it according to the standard in this paper if the foundation settlement need not.