本文關鍵詞：塊狀巖體錨固力學特性研究　出處：《中國礦業(yè)大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： 塊狀巖體 力學特性 變形特征 應力分布 錨固機理

【摘要】：塊狀巖體作為一種常見工程巖體,其內(nèi)部的各種節(jié)理、層理等弱面對巖體結(jié)構整體穩(wěn)定性及工程安全具有重要影響。錨桿支護作為現(xiàn)在圍巖穩(wěn)定控制的主要手段,深入研究各因素下加錨塊狀巖體強度特性及變形特征,分析內(nèi)部應力分布及錨桿作用機理,對實際工程中錨桿支護設計具有重要的意義。本文以煤礦巷道頂板塊狀巖體為研究對象,利用物理模型試驗及數(shù)值模擬,對不同塊體特征及不同錨固條件下塊狀巖體錨固特性進行研究,分析各因素對錨固體模型強度特性、變形特征、錨桿受力及內(nèi)部應力分布的影響,并在此基礎上對塊狀巖體錨固機理進行了分析。主要研究成果如下:(1)基于巷道圍巖錨固體單元簡化力學模型,設計了類巖石錨固體試驗模擬系統(tǒng),以實現(xiàn)加錨塊狀巖體壓縮試驗過程中力學邊界條件模擬與控制;基于相似準則,主要考慮巖體、結(jié)構面及錨桿材料的相似性,進行基本力學性質(zhì)測試,并制備塊狀巖體試樣。(2)通過對不同塊體特征及錨固參數(shù)下各模型進行試驗,結(jié)果表明加錨之后,模型峰值應力及彈性模量明顯增大;隨著塊體大小、錨固長度、錨固密度及錨桿預緊力的增大,模型峰值應力及彈性模量也基本呈增大趨勢;通過因素敏感度分析發(fā)現(xiàn)基準狀態(tài)時各因素對錨固體強度的影響主次順序為:塊體大小錨固方式錨桿密度錨桿預緊力。(3)通過錨桿軸力監(jiān)測發(fā)現(xiàn)錨桿軸力隨時間主要經(jīng)歷了緩慢增長期、快速增長期、穩(wěn)定期或降低期、失效期;模型破壞形式主要有剪切滑移破壞、X型剪切破壞和剪切劈裂混合破壞,揭示了加錨塊狀巖體中錨桿的主要作用是提高結(jié)構面的抗剪強度。(4)在物理模擬的基礎上,利用非連續(xù)體離散元數(shù)值反演方法建立與物理模擬試驗相吻合的數(shù)值模型;通過研究發(fā)現(xiàn),節(jié)理及層理傾角對模型峰值強度影響明顯,節(jié)理1及層理傾角對彈性模量也有明顯影響,而節(jié)理2對模型彈性模量影響較小。(5)錨桿對錨固體模型位移場及應力場有明顯影響,由于錨桿作用而在模型中形成錐形壓縮區(qū),且相鄰錨桿作用形成的壓縮區(qū)相互疊加而形成錨固帶;塊體沿模型內(nèi)部弱面有明顯的滑移,且在弱面位置發(fā)生明顯的應力變化。塊狀巖體錨固機理是通過錨桿的擠壓作用提高結(jié)構面強度特性,改善巖體受力特性,進而提高錨固體承載特性。
[Abstract]:As a common engineering rock mass, massive rock mass has various joints in its interior. The whole stability and engineering safety of rock mass structure with weak face such as bedding have important influence. Anchor support is the main means of stability control of surrounding rock. The strength and deformation characteristics of bolted rock mass under various factors are studied deeply, and the internal stress distribution and anchoring mechanism are analyzed. This paper takes the roof block rock mass of coal mine roadway as the research object, using physical model test and numerical simulation. This paper studies the anchoring characteristics of block rock mass under different block characteristics and different anchoring conditions, and analyzes the influence of various factors on the strength characteristics, deformation characteristics, bolt force and internal stress distribution of anchor body model. The main research results are as follows: (1) based on the simplified mechanical model of roadway surrounding rock Anchorage unit, a rock Anchorage test simulation system is designed. In order to realize the simulation and control of mechanical boundary conditions in the compression test of bolted rock mass; Based on the similarity criterion, the similarity of rock mass, structural plane and anchor material is considered, and the basic mechanical properties are tested. The results show that the peak stress and elastic modulus of the model increase obviously after anchoring. With the increase of block size, anchoring length, anchoring density and anchor pre-tension force, the peak stress and elastic modulus of the model also show an increasing trend. Through factor sensitivity analysis, it is found that the influence of various factors on the strength of anchor body is in the order of: block size anchoring mode anchor bolt density anchor pre-tension force. Through the monitoring of the axial force of the anchor rod, it is found that the axial force of the bolt has mainly experienced a slow growth period with time. Rapid growth period, stable period or decrease period, failure period; The failure modes of the model are mainly shear slip failure X type shear failure and shear split mixed failure. It is revealed that the main function of anchor rod in bolted block rock mass is to improve the shear strength of structural plane. (4) on the basis of physical simulation. The discrete element numerical inversion method of discontinuities is used to establish a numerical model which is consistent with the physical simulation test. It is found that joint and bedding dip angle have obvious influence on the peak strength of the model, and joint 1 and bedding dip angle also have obvious influence on elastic modulus. Joint 2 has little effect on the elastic modulus of the model.) the anchor rod has obvious influence on the displacement field and stress field of the Anchorage model, and the conical compression zone is formed in the model because of the effect of the anchor rod. And the compression zone formed by the action of adjacent bolt superposes with each other to form the anchoring zone; The block has obvious slip along the weak plane of the model and obvious stress changes in the weak plane. The anchoring mechanism of block rock mass is to improve the strength characteristics of the structural plane and the stress characteristics of the rock mass through the extrusion action of the anchor rod. Furthermore, the bearing characteristics of anchors are improved.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TD353

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