现代隧道技术
現代隧道技術
현대수도기술
Modern Tunnelling Technology
2015年
5期
32-39
,共8页
深埋隧洞%岩爆%岩石强度%岩体完整性%形成条件%数值模拟
深埋隧洞%巖爆%巖石彊度%巖體完整性%形成條件%數值模擬
심매수동%암폭%암석강도%암체완정성%형성조건%수치모의
Rock burst%Rock strength%Integrality of rock mass%Forming conditions%Numerical simulation
岩体的结构与性质是岩爆发生与否的物质基础,也是岩爆发生的主要内因. 深埋地下隧洞中的岩爆灾害主要产生于坚硬的弹脆性围岩中. 强度高、原生节理裂隙少、岩体完整性好等岩体条件非常有利于岩石积累弹性应变能. 为定量分析岩体条件对围岩潜在岩爆可能性的影响,文章针对锦屏Ⅱ级水电站深埋地下隧洞工程实例,采用岩石单轴抗压强度表征围岩的强度, 采用地质强度指标GSI刻划岩体的完整性程度; 保持围岩应力水平条件不变,选取不同的岩石单轴抗压强度和不同的地质强度指标,通过数值模拟方法分别计算围岩应力集中部位在开挖过程中的应力变化特征及最终应力状态. 数值计算结果揭示,深埋地下隧洞的强岩爆主要倾向于出现在强度高、岩石单轴抗压强度达到120 MPa以上、岩体完整性好、地质强度指标GSI值在55以上的Ⅱ级围岩.
巖體的結構與性質是巖爆髮生與否的物質基礎,也是巖爆髮生的主要內因. 深埋地下隧洞中的巖爆災害主要產生于堅硬的彈脆性圍巖中. 彊度高、原生節理裂隙少、巖體完整性好等巖體條件非常有利于巖石積纍彈性應變能. 為定量分析巖體條件對圍巖潛在巖爆可能性的影響,文章針對錦屏Ⅱ級水電站深埋地下隧洞工程實例,採用巖石單軸抗壓彊度錶徵圍巖的彊度, 採用地質彊度指標GSI刻劃巖體的完整性程度; 保持圍巖應力水平條件不變,選取不同的巖石單軸抗壓彊度和不同的地質彊度指標,通過數值模擬方法分彆計算圍巖應力集中部位在開挖過程中的應力變化特徵及最終應力狀態. 數值計算結果揭示,深埋地下隧洞的彊巖爆主要傾嚮于齣現在彊度高、巖石單軸抗壓彊度達到120 MPa以上、巖體完整性好、地質彊度指標GSI值在55以上的Ⅱ級圍巖.
암체적결구여성질시암폭발생여부적물질기출,야시암폭발생적주요내인. 심매지하수동중적암폭재해주요산생우견경적탄취성위암중. 강도고、원생절리렬극소、암체완정성호등암체조건비상유리우암석적루탄성응변능. 위정량분석암체조건대위암잠재암폭가능성적영향,문장침대금병Ⅱ급수전참심매지하수동공정실례,채용암석단축항압강도표정위암적강도, 채용지질강도지표GSI각화암체적완정성정도; 보지위암응력수평조건불변,선취불동적암석단축항압강도화불동적지질강도지표,통과수치모의방법분별계산위암응력집중부위재개알과정중적응력변화특정급최종응력상태. 수치계산결과게시,심매지하수동적강암폭주요경향우출현재강도고、암석단축항압강도체도120 MPa이상、암체완정성호、지질강도지표GSI치재55이상적Ⅱ급위암.
Structural properties of rock masses are the material basis and main factors for rock burst occurrences. In deep tunnels, most rock bursts occur in hard surrounding rock characterized by elasto-friability. Sound condi-tions for rock masses, such as high strength, fewer original joint fissures and good integrality, are conducive to e-lastic strain energy accumulation in rock masses. In order to quantitatively analyze the influence of rock mass conditions on the possibility of rock bursts in surrounding rocks, and using the deep tunnel of the Jinping Ⅱ hy-dropower station as an example, the uniaxial compressive strength of a rock mass is selected to represent the strength of the surrounding rock and the geological strength index (GSI) is selected to represent the integrality of the surrounding rock mass. With an unchanged surrounding rock geo-stress, different uniaxial compressive strengths and various geological strength indexes, the stress behaviors and ultimate stress state at the stress con-centration zones during tunnel construction are calculated by a numerical simulation. The numerical calculation results indicate that intense rock bursts mostly occur in surrounding rock masses of Class Ⅱ characterized by high strength (uniaxial compressive strength>120 MPa) and good integrality (geological strength index>55).
