黄土洞室掘进深度与围岩位移变化规律研究

应用PLAXIS 2D/3D有限元分析软件,对某黄土洞室进行了二维、三维分步掘进、三维一次掘进等工况的弹塑性有限元分析,研究分析了不同工况下洞室围岩位移的变化规律,并对掌子面的空间效应进行了分析。分析结果表明,二维与三维分步计算的最终位移基本一致,可以用二维的计算结果来估算洞室开挖的最终位移。三维分步掘进的分析表明,不同埋深的洞室其位移比的变化规律基本一致,当L/B<1时(L为掘进深度,B为洞室跨度),位移比呈线性增加;当L/B>1时,位移比呈非线性增加;当L/B>3时,其最大位移接近最终位移。掌子面的空间效应分析表明,在掌子面处的位移约为最终位移的1/3,距掌子面0.5倍跨度处的位移约为最终位移的2/3,距掌子面2.5倍跨度处的位移基本达到了最终位移。     

Experimental Analysis on Deformation Evolution and Crack Propagation of Rock Under Cyclic Indentation

Indentation-induced cracking may have many implications in rock drilling and cutting processes. In the present work, cyclic indentation tests have been conducted on Yunnan sandstones to investigate the deformation and failure process. Deformation fields on the sample surface have been obtained via the digital image correlation (DIC) technique. It has been found that the macroscopic force–indentation curve exhibits hysteresis and the residual displacements increase during the loading–unloading cycles. Furthermore, a median crack has been observed to nucleate, running almost parallel to the loading axis when the indentation force amounts to a critical value. Such a crack always results in the final failure of the sandstone samples. Experimental analysis reveals the deformation and failure mechanism of sandstone during cyclic indentation. By the DIC technique, the displacement distribution along the crack surface can be easily calculated and, hence, the fracture parameters, such as crack opening displacement and fracture toughness.     

天摩岭公路隧道施工围岩位移监测技术

介绍了浙江省台州天摩岭公路隧道施工中的围岩位移监测技术，包括隧道周边、拱顶、地表的监测点布置与量测分析方法，并对监测结果进行分析，以指导隧道的设计与施工。     

页岩中开挖洞室的塌方预报及判据

本文介绍了清江隔河岩电站厂房高边坡201夹层处理时页岩中洞室开挖的稳定性监测。在实测变形的基础上划分出等速变形和加速变形阶段,根据T_i与T_(i-1)关系建立了页岩失稳判据和塌方预报方法,并且在工程建设中成功地进行了8次预报,保证了施工安全     

New Systematic Method to Determine Elastic Constants and Crack Propagation Thresholds of Brittle Rocks Under Triaxial Compression

Geotechnical and Geological Engineering - Elastic constants and crack propagation stress thresholds of brittle rocks are important mechanical properties for engineering applications. However, these...     

岩石材料单轴受压变形特性的数字云纹法测定

在简要地介绍了数字云纹法应变测量的基本原理以及实施方法的基础上,对这一方法在岩石材料上应用的可行性进行了验证,通过对粉砂岩、泥贞岩、片麻岩及大理岩四种岩石弹性模量的测定,说明运用数字云纹法可对不同特性岩石材料进行测试,其精度能满足丁程要求。是电阻应变片测试方法的有益补充。     

Study on Deformation Failure Mechanism and Control Technology of Surrounding Rock in Soft Rock Roadway

Geotechnical and Geological Engineering - In order to reveal the mechanism of surrounding rock deformation and instability of soft rock roadway in 12# working face of Puhe coal mine, and...     

连拱隧道围岩变形和破坏形态的DDA分析

连拱隧道围岩一般为由节理结构面相互切割的非连续岩体,利用非连续性分析方法研究这类围岩的变形和破坏形态可以更好地反映工程实际情况。采用非连续变形分析方法 DDA,对金鸡山连拱隧道围岩的变形和破坏过程进行了模拟,将整个变形破坏过程划分为了3个阶段：中墙上方岩体变形、地表下沉、滑移面产生阶段、隧道左右洞两侧滑移带（或滑移面）的形成阶段以及中墙顶部块体失稳、隧道上方岩体快速塌落阶段。研究了金鸡山隧道浅埋围岩和深埋围岩的变形破坏特征,其中边墙部位、靠近中墙的内侧拱顶或拱肩部位、外侧拱肩部位会首先受到变形破坏。     

通渝隧道围岩变形的神经网络预测

隧道新奥法施工中 ,常以围岩变形量作为评判围岩稳定性和支护结构经济合理性的重要指标。公路隧道围岩变形量是随时间而变化的数据序列 ,因而可以建立一些实时跟踪预测模型和方法。根据通渝隧道围岩拱顶下沉位移变形的特性 ,采用神经网络技术来预测其变形量 ,结果表明该方法简易、有效     

Numerical Analysis of Soft Surrounding Rock Deformation in Freezing Shaft Sinking based on Temperature Partition

Geotechnical and Geological Engineering - To master the deformation law of soft surrounding rock of well wall during freezing shaft sinking in water-rich area, the distribution of freezing...     

Research on Creep Deformation and Control Mechanism of Weak Surrounding Rock in Super Large Section Tunnel

Geotechnical and Geological Engineering - In order to solve the difficulties of creep deformation of surrounding rock in super large section tunnel, taking Letuan tunnel of Binlai expressway, a...     

崔家冲隧洞软弱围岩注浆工法的研究应用

长沙引水及水质环境工程崔家冲隧洞要穿越区域性高棱山压扭性断层F86,断层宽度达100余米,长度达1000余米,洞顶以上地表覆盖层达110 m,其规模为同类工程所罕见。由于断层破碎带岩体强度低,透水性好,穿越断层破碎带洞段的施工成为工程建设中的重点和难点。所以隧洞在施工过程中需采用多种方法穿越众多的不良地质段。主要介绍和探讨了该隧洞穿越F86断层破碎带所采用的超前预注浆技术、超前支护技术及长管棚施工技术,为今后在类似工程中提供施工借鉴。     

距离判别法在公路隧道围岩分类中的应用

将距离判别分析方法应用于公路隧道围岩类别判定问题中,结合前人研究经验,选用隧道洞室围岩岩石单轴饱和抗压强度σc、节理平均间距d、岩石质量指标RQD、地下水情况作为围岩类别判定的距离判别分析模型判别因子,以前人实际工程中公路隧道围岩实测数据资料作为训练样本进行分析计算,建立围岩类别判定的距离判别分析模型。采用回判估计方法对判别结果进行验证,误判率为零,将对样本数据的回判结果与前人应用神经网络方法判别结果对比,判别结果一致。运用距离判别分析模型对浙江省诸永高速公路枫树岭隧道围岩类别情况进行判别,将所选洞段围岩情况判定为Ⅳ类,与规范方法判定结果一致。     

危岩裂缝扩展研究及捆绑法在危岩边坡治理中的应用

文章以某滑塌式危岩体为例建立了危岩体的有限元计算模型,分析了影响危岩体稳定性的因素,讨论了危岩体开裂深度对危岩体稳定性的影响及危岩裂缝开展的破坏演化机制,并结合规范采用理正软件对本文提出的捆绑法治理滑塌式危岩体的可行性进行了验证。稳定性分析的结果表明:采用捆绑法治理后,危岩体在自然工况、暴雨工况和地震工况下的稳定性系数都能保证危岩体处于稳定状态,为危岩体的防治提供了一种新的思路。     

Study on Monitoring Technology of Surrounding Rock in Deep Layered Roadway Based on Constant Resistance and Large Deformation Bolt

Geotechnical and Geological Engineering - The stability monitoring of surrounding rock in layered roadway is an important method to ensure the safety of deep mining coal mine. In view of the actual...     

井筒及围岩应力,应变观测方法研究

采用最新研制的岩体应力、应变匹配传感器对西安立井煤柱开采引起的井筒附加应力特别是对井筒穿过断层附近产生的附加应力进行了较系统的观测，并对观测结果进行了分析和总结。     

Deformation Field around the Stress Induced Crack Area in Sandstone by the Digital Speckle Correlation Method

Abstract: The deformation field around sub-cracks was calculated using the digital speckle correlation method. First, the uni-axial compression tests on sandstone samples containing a pre-fabricated fracture were made. Photomicrographs showing the characteristics of the sub-crack development were taken using a scanning electron microscope (SEM). From these photomicrographs, the real-time images showing the initiation, growth and coalescence of sub-cracks and micro-cracks in the sandstone specimens were obtained and the effects of loading level as well as grain boundaries on the development of cracks were analyzed. Second, the intensity images of the sandstone specimen surface were captured from the observations of the SEM corresponding to different loading levels. Then correlation computation was carried out for the sequential pairs of intensity images to evaluate the displacement components, as well as the strain field. The results show that the deformation varies in different areas separated by sub-cracks during rock damage processes.