排序方式： 共有61条查询结果，搜索用时 15 毫秒
1.
本文通过对泥浆性能的分析,特别是对泥浆流变参数的控制与调节在定向钻进非开挖铺管中的作用及其护壁原理的分析,简要阐述了泥浆性能对定向钻进铺管孔壁稳定性的影响,对非开挖定向钻进铺管施工有一定的指导意义。 相似文献
2.
黄土路堑边坡变形破坏机理的三轴试验研究 总被引：1，自引：0，他引：1
通过原状黄土的减压三轴压缩试验,研究了黄土边坡不同深度不同含水量土体的应力-应变关系,并与原状黄土的常规三轴试验结果进行了比较,发现减压三轴试验能合理地模拟和解释开挖卸荷作用下黄土边坡土体的变形与破坏过程。试验结果表明:坡脚开挖卸荷时,黄土边坡中浅层非饱和黄土易出现应变软化或塑性流动,强度较低,易产生较大变形,而深层饱和黄土仅在高围压下发生应变硬化,强度增加,在中低围压时均发生应变软化现象。分析认为黄土边坡特殊的工程地质条件,使得黄土边坡的特定部位在开挖卸荷作用下常形成了不利于土体稳定的含水量和围压组合,导致坡体特定部位的土体变形破坏,进而诱发边坡的变形破坏;开挖卸荷作用下黄土边坡变形破坏的力学机制应为蠕滑-压致拉裂或牵引式滑坡。 相似文献
3.
Investigating the effect of soil models on deformations caused by braced excavations through an inverse-analysis technique 总被引：1，自引：0，他引：1
In this study, a series of inverse-analysis numerical experiments was performed to investigate the effect of soil models on the deformations caused by excavation by using the finite element method. The nonlinear optimization technique that was incorporated into the finite element code was used for the inverse-analysis numerical experiments. Three soil models (the hyperbolic model, pseudo-plasticity model, and modified pseudo-plasticity model) were employed in the intended numerical experiments on a well-documented excavation case history. The results indicate that wall deflection due to excavation can be accurately back-figured by each of the three soil models, while the ground surface settlement can be reasonably optimized only by the pseudo-plasticity model and the modified pseudo-plasticity model. Importantly, the modified pseudo-plasticity model can yield more reasonable simulations when the wall deflection and the ground surface settlement are simultaneously back-figured. The results show that selection of an adequate soil model that is capable of adequately describing the stress–strain-strength characteristics of the soils is essentially crucial when predicting the excavation-induced ground response. 相似文献
4.
5.
洞室开挖不可避免地会损伤岩体, 对于规模巨大、布置异常复杂的水电地下厂房围岩尤甚, 合理地确定开控损伤区(EDZ)分布成为地下洞室的信息化设计、施工和安全运营的关键性问题.在引入EDZ概念及强EDZ、弱EDZ和基本未损区分区的基础上, 提出采用声波测试方法来确定强EDZ和弱EDZ的分布.将声波波速-深度曲线划分为Ⅰ型、Ⅱ型和Ⅲ型等3种曲线类型, 根据曲线特征点, 对EDZ进行定性、半定量的初判.根据波速计算得出的损伤因子D, 对强、弱EDZ和基本未损区进行定量的判别.首次提出的基于声波测试法, 定性、半定量和定量相结合的综合研判法具有创新性, 为客观评价地下洞室EDZ提供了科学的方法. 相似文献
6.
7.
王晓鸿 《地质灾害与环境保护》1999,10(1):72-78
从目前施工面临的问题出发,利用人工智能工具ＣＬＩＰＳ语言建立一个简单的基于知识的基于基坑施工监控器,主要用于解决监测数据的自动查错、变形趋势预测、变形自动报警,以及具有自学习的施工应急措施。 相似文献
8.
In Korea, a reference disposal system, KRS, was proposed in 2006 after 10 years of research and development. In the KRS, the high-level radioactive waste repository is considered to be located in a crystalline rock likes granite. For a validation of the feasibility, safety, and stability of the KRS, an underground research tunnel, KURT was constructed in Nov. 2006. During the construction of KURT by a controlled blasting, the size and characteristics of an excavation damaged zone(EDZ) were investigated by in situ as well as laboratory tests. The possible influences of an EDZ around a tunnel on the thermal, hydraulic and mechanical behaviors of the near field were investigated by using hydro-mechanical and thermo-mechanical coupling analyses. From this study, it was found that the existence of an EDZ can influence the thermal, hydraulic, and mechanical behaviors of the near field and it was recommended that an EDZ should be considered as an important parameter during the design of underground repositories. 相似文献
9.
By using the axisymmetric finite elements static limit analysis formulation, proposed recently by the authors, the stability numbers (γH/co) for an unsupported vertical circular excavation in clays, whose cohesion increases with depth, have been determined under undrained condition; γ = unit weight, H = height of the excavation and co = cohesion along ground surface. The results are obtained for various values of H/b and m; where b = the radius of the excavation and m = a non-dimensional parameter which accounts for the rate of the increase of cohesion with depth. The values of the stability numbers increase continuously both with increases in H/b and m. The results obtained in this study compare well with those available in literature. 相似文献
10.
The Boom clay is considered as a candidate host rock for the Belgian disposal of radioactive waste. Thanks to the recent sinking
of a new shaft to extend the Underground Research Laboratory (URL) at the Mol site, new in-situ data have been obtained. They
consist in the observation of significant fracturing, evidenced during the excavation of the shaft annexes, and in correlated
hydraulic perturbations in the far field (maximum of 0.2 MPa at 60-m radius). These observations cannot be explained from
simple poroplastic models that predict a maximum perturbation extent of 25 m under full deconfinement. Thus, models with increasing
complexity are built to explain this discrepancy. It is proposed that the low-support pressure imposed by the primary lining,
combined with the long time over which this support condition held, has favoured the decompression of the clay massif through
time-dependent effects, mainly skeleton viscosity. This resulted in near-field fracturing, leading to an apparent increase
of the excavated radius and to a hydraulic perturbation in the far field. This interpretation still needs to be validated/invalidated
with future research. The effect on the overall performance of the repository is expected to remain small due to the self-healing
nature of the fractures.
Electronic Publication 相似文献