| With gradually strained urban construction land and the rapid development of the municipal engineering construction,there are more and more deep and large foundation pits.The engineering construction puts forward higher request to the foundation pit support.Anchor supporting method,as an important supporting effect is good,easy construction and have the distinct advantage of noninterference construction operation at the same time.For deep foundation pit,anchor structure faces can be extremely complex geological conditions,the groundwater to the erosion of anchor structure should not be neglected.In addition,the length of anchor used in deep and large foundation pits is relatively long,and the steel bars or steel strands buried in the soil are likely to bring obstacles to surrounding construction.Under these conditions,the application of FRP anchor solves these problems well.The glass fiber reinforced(GFRP)material has a higher tensile strength than the steel bar,and does not have the problem of corrosion.At the same time,it is easy to cut when it affects the later construction.In this paper,based on the foundation pit supporting engineering of Beijing subway station,GFRP reinforcement grouting slurry with higher construction performance was developed by grouting ratio test.Through the anchor solid test,the failure law and failure development process of the anchor solid specimen of different bolt materials,bolt forms and grouting materials were studied,and the influence of different variables was analyzed,which provided a reference for the use and selection of GFRP bar anchor in engineering.In the construction of the anchor structure using GFRP bars in the support engineering site,the engineering performance is verified through the basic test,and the law of failure is analyzed through numerical simulation.The contents of this paper provide some references for the research on the failure mechanism of GFRP bar anchors,and the specific results obtained are as follows:1)Based on the common grout in engineering,a new grout material with fast setting and hardening,high early strength,good fluidity,good water retention and small volume expansion has been developed by means of the grout ratio test.The grouting material can be hardened in one day to meet the requirements of prestressing tension.At the same time,it pays attention to the bleeding rate,which is less paid attention to in previous studies.The grout has good water retention performance,while the volume expands slightly,which provides a guarantee for better exerting the tensile performance of the anchor bolt.2)Through the larger size of the anchor solid test,the anchor solid specimens with different materials,different number of reinforcement,different structure forms and different slurry types were pulled out.During the test,the stress-strain and displacement changes during the loading process were monitored and the failure phenomena were recorded.Through the comparative analysis of the test results,the working and failure rules of GFRP bar anchor,the performance difference of different types of anchor materials,the bearing capacity difference of anchor structure and the bearing capacity difference of anchor caused by the application of new type of grout were studied.In this paper,the failure mechanism of GFRP bar anchor is studied comprehensively by analyzing the stress strain and displacement development law of bars and the failure mode of anchor.3)Through the basic test and numerical simulation calculation of the GFRP bar anchor in the engineering field,the working performance and failure process of the engineering anchor in the bearing process are studied,and the stress development law of the surrounding rock and soil mass is analyzed in the stress process of the anchor,and the failure mechanism research of the GFRP bar anchor is improved.The research of this paper has a certain guiding significance for the design and application of GFRP bar anchors.GFRP bar anchors have reliable performance and easy construction,which can be popularized and applied in similar projects later. |
