注浆伞型锚锚固特性现场试验研究  

Field Test of Grouted Umbrella-Shaped Ground Anchors

作　　者：冯党 黄鹏 FENG Dang;HUANG Peng(Headwork Division of Construction Administration,Bureau of Middle Route of South to North Water Diversion Project,Nanyang 473000;Yangtze River Scientific Research Institute,Wuhan 430010)

机构地区：[1]南水北调中线干线工程建设管理局渠首分局,河南南阳473000 [2]长江科学院水利部岩土力学与工程重点实验室,武汉430010

出　　处：《土工基础》2021年第1期86-90,共5页Soil Engineering and Foundation

基　　金：国家重点研发计划水资源高效开发利用(2017YFC0405002);青年科学基金项目(51709016);长江科学院“中央级公益性科研院所基本科研业务费”项目(CKSF2019199/YT)。

摘　　要：为了研究在膨胀土边坡快速抢险加固中伞型锚的锚固效果及控制方式,开展无浆或注浆伞型锚以及不同长度的常规注浆锚杆的现场拉拔工艺试验,测试了无浆或注浆伞型锚以及不同长度注浆锚杆的极限抗拔力。研究表明:(1)在一定长度范围内,常规注浆锚杆的极限抗拔力与锚固长度呈线性关系,抗拔力随着位移的增加先快速非线性增加,然后缓慢线性增加;(2)因为注浆所产生的粘结力在锚杆位移到一定距离时会失去效果,为了使伞型锚与注浆作用同时叠加发挥,应该对伞型锚进行合理预张拉,使得两者同时发挥最大抗拔力,提高极限强度,注浆可以使锚固段形成整体,受力更均匀,注浆后伞型锚达到破坏标准时仍具有一定的持荷能力,说明锚固段完整,仍有一定锚固能力;(3)当伞型锚仅需在滑体外的原状土体中进入15 m时,常规注浆锚杆在滑体外的有效锚固长度约为21 m,才可以提供与伞型锚相当的极限抗拔力。可知伞型锚对边坡的支护效果比常规注浆锚杆好,适合于膨胀土边坡快速抢险加固。In order to evaluate the anchoring effect and the control failure mode of the umbrella-shaped ground anchor in the rapid reinforcement of expansive soil slope failures,and to further increase the anchoring results with permanent corrosion protection,a series of field tests were performed on the umbrella-shaped ground anchors with/without grouts and with various anchoring length.The following results can be obtained:1.In an anchor grouted length range,the ultimate pull-out resistance of the conventional grouted ground anchor demonstrates a linear with the bonding length,while for the grouted umbrella-shaped ground anchor,the pull-out resistance first increases nonlinearly with the increase of displacement rapidly,and then the pullout resistance increases linearly gradually with the displacement value;2.Since the adhesion between anchor and the surrounding soils induced by the grouts will reach its ultimate value when the displacement of anchor reaches a critical value,apre-tension load should be applied on the umbrella-shaped anchors so that the ground anchor can reach a much higher pull-out resistance by mobilizing both the umbrella effect and the grouting effect at the same time.After the grouting of the umbrella-shaped ground anchor,the bonding zone can be integrated so that the bonding zone can have a more uniform stress distribution.When the umbrella-shaped ground anchor reaches the ultimate resistance,it still can maintain the ultimate load;3.Compared with the conventional ground anchor,which need to have an effective length beyond the sliding zone of 21 meters,only 15 meters are necessary for the grouted umbrella-shaped ground anchor with the same pull-out resistance.It is concluded that the new ground anchor has advantages over the conventional ground anchors and can be used in the rapid response of failures in expansive slopes.

关 键 词：伞形锚 注浆锚杆 极限抗拔力 锚固特性 

分 类 号：TU413[建筑科学—岩土工程]