CAJ | 학술논문

将强度折减法引入刚体平动运动单元上限有限元并编制计算程序，针对椭圆形毛洞隧道围岩稳定性和破坏模式开展计算分析，获得了围岩抗剪强度参数、隧道埋深、跨度等与安全系数的关系曲线，并探讨了围岩强度折减极限状态对应的刚性块体破坏模式的形态特征.结果表明：强度折减法可方便嵌入运动单元上限有限元非线性规划模型；围岩安全系数与其围岩强度参数正相关，与埋深比和跨度比负相关；隧道跨度对安全系数的影响较为明显，当隧道跨度与高度比(B/D )由0.5增加到2.0时，安全系数降低幅度处于27%~46%之间；强度折减极限状态下刚体平动运动单元上限有限元所得围岩破坏模式形态鲜明，其主要滑动破坏面由隧道底部或边墙处延伸至地表，错动的滑移线集中于隧道拱部和边墙上方，而水平破坏区域延伸范围均小于1.5倍隧道高度.
장강도절감법인입강체평동운동단원상한유한원병편제계산정서，침대타원형모동수도위암은정성화파배모식개전계산분석，획득료위암항전강도삼수、수도매심、과도등여안전계수적관계곡선，병탐토료위암강도절감겁한상태대응적강성괴체파배모식적형태특정.결과표명：강도절감법가방편감입운동단원상한유한원비선성규화모형；위암안전계수여기위암강도삼수정상관，여매심비화과도비부상관；수도과도대안전계수적영향교위명현，당수도과도여고도비(B/D )유0.5증가도2.0시，안전계수강저폭도처우27%~46%지간；강도절감겁한상태하강체평동운동단원상한유한원소득위암파배모식형태선명，기주요활동파배면유수도저부혹변장처연신지지표，착동적활이선집중우수도공부화변장상방，이수평파배구역연신범위균소우1.5배수도고도.
To study the unlined elliptical tunnel stability,strength reduction method was introduced in-to the finite element upper bound method.The relations between safety factor and influence factors such as shear strength parameters,buried depth and span were studied with self-made program.Meanwhile,the failure modes were also explored for limit states derived from strength reduction method.The results show that strength reduction method can be easily embedded into finite element upper bound method.The rela-tion curves have shown a positive correlation between rock safety factors and shear strength parameters, while rock safety factors have negative correlations with buried depth and span.The influence of the tunnel span on the safety factor is obvious,and the reduction in rock safety factors has been found to vary approx-imately in a range of 27%~46% when the ratio of tunnel span and height (B/D )increases from 0.5 to 2.0.The failure modes with distinct characteristics reveal that the main slip surface starts from the bottom or the side wall of the tunnels and then extends up to the ground surface.The slip lines are mainly focused on the top of the tunnel arch and side wall.Meanwhile,horizontal extents of the damage area are less than 1.5 times of tunnel height.