岩石GFRP抗浮锚杆承载性能室内试验与机理分析

Full-scale test and mechanism analysis on bearing capacity of GFRP anti-floating anchor socketed into rock

基于4根岩石GFRP抗浮锚杆的室内足尺拉拔破坏性试验,探讨了风化岩地基中全长黏结GFRP抗浮锚杆的界面黏结特性和承载性能,揭示了GFRP锚杆的细观破坏机理。结果表明:GFRP抗浮锚杆发生拔出破坏,主要是由螺纹表面劣化所引起的剪胀破坏;直径25mm、灌浆体强度M30、锚固长度1.3和0.55m的GFRP抗浮锚杆的极限抗拔承载力分别为255、195kN,满足工程抗浮要求;GFRP抗浮锚杆杆体与灌浆体界面平均黏结强度介于2.41~5.10MPa之间,高于《岩土锚固与喷射混凝土支护工程技术规范》(GB 50086—2015)中钢锚杆与灌浆体的黏结强度推荐值。

Based on the laboratory full-scale tensile failure tests on four full-bonded GFRP anti-anchors socketed into rock,the interfacial adhesion and bearing capacity of the anchor on rock foundation were studied,from which the micro-failure mechanism of the anchor was revealed.The results show that the pull-out failure occurred in GFRP anti-floating anchor,attributing to the dilative shear failure from anchor thread＇s interfacial deterioration.The ultimate uplift bearing capacity of GFRP anti-floating anchor with diameter of 25 mm,concrete of M30,anchorage length of 1.3 mand 0.55 m,was 255 kN and 195 kN,respectively,indicating that the high bearing capacity of the anchor for anti-floating purpose.The average bond strength between GFRP anti-floating anchor and grouting body was between 2.41 MPa and 5.10 MPa,higher than the recommended values from Technical Code for Engineering of Ground Anchoring and Shotcrete Support＂（GB 50086-2015）.