论文部分内容阅读
泥水平衡盾构以压力泥浆支护开挖面,泥膜的形成对开挖面稳定非常重要,尤其对高渗透性地层,在泥膜形成的过程中泥浆会穿透开挖面土体形成一定范围的渗透带,泥浆渗入地层后会改变原有土体的结构和物理力学性质。采用三轴试验研究了一般应力状态下泥浆渗入对砂质地层泥水盾构开挖面土体强度的影响,以粉细砂和中粗砂为研究对象,研究不同泥浆类型在一般应力条件下对开挖面土体强度参数的影响规律。研究结果表明,中粗砂和粉细砂在注浆前后,黏聚力均升高,中粗砂升高了约20倍,相对粉细砂而言,上升得更加明显;而对于内摩擦角,两种土体均表现出下降的趋势,中粗砂约降低了21%,降低幅度也较粉细砂要大;N1型和N2型泥浆对于中粗砂的强度都具有增强效果,但N1型泥浆和N2型泥浆的开挖面土体强度的影响仍有区别,注入N1型泥浆强度提高了约48%,而注入N2型泥浆提高了约29%,这说明不同类型泥浆对开挖面土体的强度影响不同。
The mud-water balance shield is supported by pressure mud and supports the excavation surface. The formation of mud membrane is very important to the stability of the excavation surface. Especially for the highly permeable formations, the mud penetrates through the excavation surface and forms a certain amount Range of infiltration zone, mud infiltration into the formation will change the original soil structure and physical and mechanical properties. Triaxial tests were carried out to study the influence of mud infiltration on the strength of soil in the excavation of slurry shield in sandy soil under normal stress conditions. The effects of different types of mud on the strength of excavated soil were studied under normal stress conditions Influence law of strength parameters of excavated surface soil. The results show that the cohesion of coarse sand and fine sand before and after grouting increases and the coarse sand increases about 20 times, which is more obvious than that of fine sand. For the internal friction angle Both of the two soils showed a tendency of decreasing. The middle coarse sand was reduced by about 21% and the decrease rate was also larger than that of the fine sand. Both N1 and N2 muds had an enhancement effect on the strength of the coarse sand, but N1 There is still a difference between the strength of excavated surface soil and mud type N2 mud, the strength of injected N1 mud increased about 48%, while the injection of N2 mud increased about 29%, indicating that different types of mud on the excavation surface Soil strength has different effects.