The Analysis On Uplift Resistance Of Rock Bolt Foundation For An Industrial Workshop

Built directly on the bedrock and with higher plant,the foundation is under large bending moment and horizontal force and use rock bolt foundation.The anchor is designed as column base bolts in steel frame.The pullout resistance of the plant column foundation is studied and analyzed in finite element method to ensure smooth execution of engineering and to provide a theory and practical introduction.For example,37(5% of all in G column)anchor foundations are sampled to carry out uplift bearing capacity examination.The axial uplift bearing capacity of all tested anchors can achieve the designed 160 KN.With a few exceptions in the continues loading process,the rest do not appear significant failure characteristics and achieve 260 KN.By the analysis of experimental data,an effective model based on the ANSYS finite numerical element simulation software is established.Then the experiment data and ANSYS analysis of uplift capacity are compared.The result is identical and verifies the validity of the model under the influence of anchor pullout force.Based on it,using finite element of the influences of pullout resistance on anchoring system are explored.Firstly,the elastic modulus of rock is studied.Through the displacement curve of anchor free end,the displacement is rather changeable when the elastic modulus range among 15 to 35 GPa which reveals the anchor is especially important to the rock bolting system when the elastic modulus of rock is smaller.The displacement drives to stability when the elastic modulus reach 60 GPa which reveals the anchoring effect is not obvious when the rock has great stiffness.The effect of anchor-concrete's bond strength on the anchorage system is discussed: When the adhesion is small,bolt is pulled out as the load increases and anchor works in the elastic state in this process.This type of destruction is due to the lack of interface bond strength.When the adhesion is larger,anchor firstly works in the elastic state,then enters into the plastic state.Then the load continues to increase,and the anchor is pulled out and the anchor system is destroyed.The result shows that the pullout resistance surpluses a lot,so the effect of different anchorage depthson the anchor system is studied at last.It shows that the pullout resistance reaches 194 KN,1.2 times of the the original designd 160 KN,when the anchorage depth reaches 2.5m.At last,by analysis of the relationship between bolt diameter and anchorage depth is summarized.In a word,the improvement of bolt tensile strength and interface bond strength can improve the pullout the bearing capacity of anchor system,and an appropriate anchorage depth choice can economize the cost and the project construction time efficiently.