玻璃钢螺旋锚用于稳定膨胀土渠坡的现场拉拔试验和锚筋的破坏形式

Field pull-out tests and failure model of GFRP screw anchors used to stabilize canal slopes of expansive soils

介绍了采用玻璃钢螺旋锚锚固河南省邓州市引丹灌区北干渠膨胀土渠道水上渠坡的混凝土框架梁节点和水下渠坡的混凝土板,联合土工格栅、土工泡沫(EPS)用于修复该渠道滑坡试验段(长50 m)的锚杆现场拉拔试验。无灌浆锚杆的拉拔力在30 kN以上(平均36 kN),灌浆锚杆的拉拔力在37 kN以上(平均45 kN)。分析了锚固参数如上覆土层厚度、锚杆钻进长度以及锚固后至拉拔前的时间间隔、灌浆锚杆拉拔时锚具附近锚筋的劈裂破坏等对玻璃钢螺旋锚抗拔力和拉拔位移的影响,并分析了锚固的土类对玻璃钢螺旋锚最大拉拔力的影响。最后通过试验中的观察,总结了玻璃钢锚筋常见的破坏形式。

In order to repair the slide of the canal slope of expansive soil in Dengzhou County, Henan Province, China, the screw anchor made of glass fibers reinforced plastic （GFRP） is used to anchor the concrete frame girder above the berm of the canal slope of expansive soils and the concrete slab below the berm of the canal slope of expansive soils. The geogrid paved in fill soil of the canal slope improves the factor of safety against complete sliding surface, and the geofoam slab under the concrete slab is used to reduce the expansive force, and GCL under the concrete slab is used as seepage prevention liner. The field pull-out tests of GFRP screw anchor are introduced, and the test results of un-grouted and grouted anchors are presented. The average pullout force of the grouted anchors is 45 kN, and that ofun-grouted anchors is 36 kN. The influences of anchoring parameters （such as superimposed soil thickness, anchor hole length, interval time between anchoring and pullout test） and soil type on the pull-out force and pull-out displacement of GFRP screw anchor are analyzed. Finally, the failure models of GFRP screw anchor observed in the tests are summarized.