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  本文選題：節(jié)理巖體 + 聲波波速�。� 參考：《三峽大學(xué)》2015年碩士論文

【摘要】：論文選取四川雅礱江兩河口水電站邊坡砂板巖為對象，預(yù)制0°、30°、45°、60°、90°等5種貫通節(jié)理，對預(yù)制節(jié)理試樣進(jìn)行了聲波波速測試，開展砂板巖完整試樣和預(yù)制節(jié)理試樣的單軸壓縮試驗(yàn)，三軸壓縮試驗(yàn)及三軸卸荷試驗(yàn)，模擬巖體在不同節(jié)理傾角、不同圍壓、不同卸荷速率下的受力狀態(tài)，研究分析了砂板巖在加卸荷條件下的力學(xué)特性，并將研究成果應(yīng)用到該工程中，論文的主要研究內(nèi)容及結(jié)論如下： 1）節(jié)理試樣聲波波速測試和單軸壓縮試驗(yàn)結(jié)果表明，隨著節(jié)理傾角的增大，試樣的波速呈增大趨勢，節(jié)理巖體波速衰減率隨節(jié)理傾角的變化規(guī)律可以用二次函數(shù)來表示： V0.0000120.00210.1137。隨著節(jié)理傾角的增大，峰值強(qiáng)度和彈性模量呈U型變化，最小值出現(xiàn)在60°傾角節(jié)理試樣處。45°和60°試樣石膏面發(fā)生了錯動，其它節(jié)理試樣均發(fā)生脆性破壞，破壞面穿越了節(jié)理面。 2）三軸壓縮試驗(yàn)結(jié)果表明，對于完整試樣，隨著圍壓等級的升高，試樣的屈服特征愈加顯著；不同節(jié)理傾角下，試樣的應(yīng)力-應(yīng)變曲線形態(tài)有較大差異；完整和節(jié)理試樣的彈性模量和變形模量隨著圍壓等級的升高呈非線性增長的特征；對圍壓和峰值強(qiáng)度進(jìn)行擬合，Mohr-Coulumb準(zhǔn)則比Hoek-Brown準(zhǔn)則擬合精度高。45°、60°節(jié)理試樣為順節(jié)理面滑動破壞，0°、30°、90°節(jié)理試樣為穿越節(jié)理面的破壞，表明節(jié)理試樣的破壞特征具有各向異性特征。 3）三軸卸荷試驗(yàn)結(jié)果表明，加載階段試樣的力學(xué)特性與三軸壓縮試驗(yàn)相似，，在卸荷階段，45°和60°節(jié)理傾角試樣卸荷之后應(yīng)力幾乎不變，應(yīng)變快速增長，無破壞階段，其它節(jié)理傾角試樣均存在破壞階段；變形模量隨著卸荷量的增加不斷減小，在卸荷量小于60%時減小幅度不大，卸荷量在60%-100%時為非線性大幅度減小，60°傾角節(jié)理試樣的變形模量降幅最大；節(jié)理試樣的卸荷試驗(yàn)的峰值強(qiáng)度隨節(jié)理傾角呈U型變化，60°節(jié)理試樣的強(qiáng)度最小，90°最大；卸荷對試樣強(qiáng)度參數(shù)的影響主要體現(xiàn)為對粘聚力的減��；與三軸壓縮試驗(yàn)相比，卸荷試驗(yàn)中試樣產(chǎn)生的裂紋更多，破壞程度在增加。隨著圍壓等級的升高，完整試樣和節(jié)理傾角為0°、30°、90°的試樣的破壞形式由拉剪破壞向壓剪破壞過渡，破壞面穿越節(jié)理面，45°、60°傾角節(jié)理試樣為順節(jié)理面滑動破壞，巖塊均完好；卸荷速率對節(jié)理試樣卸荷階段中的強(qiáng)度、變形、破壞特征均有不同程度的影響。 4）運(yùn)用節(jié)理試樣三軸卸荷試驗(yàn)的研究成果，對兩河口水電站某邊坡進(jìn)行二維有限元計(jì)算，開挖面附近向坡外的位移隨著卸荷速率的增大有較大幅度的增長，塑性區(qū)也在不斷擴(kuò)展，建議在實(shí)際開挖過程中考慮開挖方案對巖體卸荷速率的影響，以保證工程的順利進(jìn)行。
[Abstract]:In this paper, the sand slate of the slope of Lianghekou Hydropower Station in Yalong River, Sichuan Province is selected as the object, and 5 kinds of connecting joints are prefabricated, such as 0 擄30 擄(45 擄) and 60 擄(90 擄). The acoustic wave velocities of the prefabricated jointed specimens are measured, and the uniaxial compression tests of the intact slate and prefabricated joints are carried out. Triaxial compression test and triaxial unloading test simulate the stress state of rock mass under different joint inclination angle, different confining pressure and different unloading rate. The mechanical properties of sand slate under loading and unloading conditions are studied and analyzed. The main research contents and conclusions are as follows: 1) the results of acoustic wave velocities and uniaxial compression tests show that the wave velocities of jointed rock mass increase with the increase of joint inclination angle, and the attenuation rate of wave velocity of jointed rock mass can be expressed by quadratic function: V0.0000120.00210.1137. With the increase of the dip angle of joints, the peak strength and modulus of elasticity change in U shape. The minimum value appears at the plaster face of 60 擄inclination joint, and the brittle failure occurs in all other joints, and the failure surface passes through the joint surface. 2) the results of triaxial compression test show that the yield characteristics of the specimen become more obvious with the increase of confining pressure grade, and the shape of stress-strain curve is different with different joint inclination angle. The elastic modulus and deformation modulus of the intact and jointed specimens increase nonlinear with the increase of the confining pressure grade. The fitting of confining pressure and peak strength by Mohr-Coulumb criterion is more accurate than that by Hoek-Brown criterion. The specimen of 60 擄joint is sliding failure of 0 擄/ 30 擄/ 90 擄along the joint plane, which indicates that the fracture characteristic of the joint specimen has anisotropic characteristics. 3) the results of triaxial unloading test show that the mechanical properties of the specimens in the loading stage are similar to those in the triaxial compression test. After unloading, the stress of the specimens with 45 擄and 60 擄joint inclination angle is almost unchanged, the strain increases rapidly and there is no failure stage. The deformation modulus decreases continuously with the increase of unloading amount, and decreases little when the unloading amount is less than 60. When the unloading amount is between 60% and 100%, the maximum reduction of deformation modulus is obtained for the specimen with 60 擄inclination joint, and the maximum strength of 60 擄joint specimen is 90 擄when the unloading strength of the joint specimen varies with the U-shape angle of the joint inclination angle, and the deformation modulus of the joint specimen decreases greatly when the unloading amount is between 60% and 100%, and the maximum value is 90 擄when the unloading strength of the joint specimen is U-shaped. The influence of unloading on the strength parameters of the specimen is mainly reflected in the reduction of the cohesive force, and compared with the triaxial compression test, the specimen produces more cracks and the degree of failure increases. With the increase of confining pressure grade, the failure form of the intact specimen and the specimen with a dip angle of 0 擄or 30 擄~ 90 擄is changed from tension-shear failure to compression-shear failure, and the failure surface is sliding along the joint surface through 45 擄~ 60 擄inclined joint, and the rock block is intact. The unloading rate has different effects on the strength, deformation and failure characteristics of jointed specimens during unloading. 4) based on the research results of triaxial unloading test of jointed specimens, a slope of Lianghekou Hydropower Station is calculated by two-dimensional finite element method. The displacement near the excavation surface outside the slope increases greatly with the increase of unloading rate. The plastic zone is also expanding and it is suggested that the influence of excavation scheme on the unloading rate of rock mass should be considered in the actual excavation process in order to ensure the smooth progress of the project.
【學(xué)位授予單位】：三峽大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU45

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