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1.
This paper presents the engineering geological properties and support design of a planned diversion tunnel at the Boztepe dam site that contains units of basalt and tuffites. Empirical, theoretical and numerical approaches were used and compared in this study focusing on tunnel design safety. Rock masses at the site were characterized using three empirical methods, namely rock mass rating (RMR), rock mass quality (Q) and geological strength index (GSI). The RMR, Q and GSI ratings were determined by using field data and the mechanical properties of intact rock samples were evaluated in the laboratory. Support requirements were proposed accordingly in terms of different rock mass classification systems. The convergence–confinement method was used as the theoretical approach. Support systems were also analyzed using a commercial software based on the finite element method (FEM). The parameters calculated by empirical methods were used as input parameters for the FEM analysis. The results from the two methods were compared with each other. This comparison suggests that a more reliable and safe design could be achieved by using a combination of empirical, analytical and numerical approaches. 相似文献
2.
In this paper, preliminary support design of Kaletepe tunnel, located on Bilecik-Istanbul highway, Turkey, was analyzed by empirical and numerical methods. The rock mass rating (RMR) and rock mass quality (Q) systems were employed for empirical rock mass quality determination. Numerical analysis for the stress–strain distribution of the tunnel excavation and support systems was also carried out. The applied support performance was investigated at different sections of the tunnel route. It was seen that empirical and numerical approaches showed similar results. This indicates that when the empirical method is supported by numerical method, the preliminary support design will be more reliable. 相似文献
3.
Analysis of support requirements for a shallow diversion tunnel at Guledar dam site, Turkey 总被引：2，自引：0，他引：2
Engineering geological properties and support design of a planned diversion tunnel at Guledar dam site, which was located at the North of Ankara, Turkey were studied in this article. The main purpose of the construction of the planned tunnel is to regulate, drainage and to provide water for irrigation purposes. The diversion tunnel runs mainly through formations of limestone, sandstone and diabase. Rock masses at the site were characterized using Rock Mass Rating (RMR), Rock Mass Quality (Q), Rock Mass Index (RMi) and Geological Strength Index (GSI). RMR, Q, RMi and GSI were determined by using field data and mechanical properties of intact rock samples, measured in the laboratory. Support requirements for the planned diversion tunnel were determined accordingly in terms of the rock mass classification systems. Recommended support systems by empirical methods were also analyzed using 2D Finite Element method. Calculated parameters based on empirical methods were used as input parameters in the finite element models. The results from both methods were compared with each other. This comparison suggests that more reliable support design could be achieved by using the finite element method together with the empirical methods. 相似文献
4.
This paper encompasses the engineering geological properties of rock mass along the power tunnel of hydropower in Kohistan, Khayber Pakhtun Khawa (KPK), Pakistan. The major geological units of the study area are Chilas complex (CC) and Gilgit complex (GC) that consists mostly of igneous and metamorphic rocks. Discontinuity surveys were conducted to classify the rock mass by utilizing rock mass rating (RMR) and tunneling quality index (Q) classification systems. RMR system involves collection of data for parameters of rock strength, RQD, spacing of discontinuities, condition of discontinuities, groundwater condition and Q system involves rock quality designation (RQD), joint roughness (Jr), joint sets (Js), joint alteration (Ja), stress reduction factor (SRF) and joint water reduction (Jw). RMR values ranges from 46 to 66 (fair to good) for rock unit of Chilas complex (CC) and 50 to 58 (fair) for rock unit of Gilgit complex (GC). The evaluated values of tunnel quality by Q-system are 1.55 to 6.4 (poor to fair) for Chilas complex (CC) and 1.35 to 1.84 (poor) for Gilgit complex (GC). The required support along the tunnel route is also estimated by both classification systems. Unwedge program is used to analyze the unstable zones due to the intersection of different joint sets. Total 14 cases are analyzed in Unwedge from which 3 cases have failure potential with FOS less than 1. These failure potential blocks can become stable by applying further support of rock bolting and shotcrete layer. 相似文献
5.
This paper describes the results of the engineering geological investigations and rock mechanics studies carried out at the proposed Uru
Dam site. Analyses were carried out in terms of rock mass classifications for diversion tunnel, kinematic analysis of excavation slopes, permeability of the dam foundation and determination of rock mass strength parameters.Uru
Dam is a rock-filled dam with upstream concrete slab. The dam will be built on the Suveri River in the central part of Turkey. The foundation rocks are volcanic rocks, which consist of andesite, basalt and tuff of Neogene Age. Studies were carried out both at the field and the laboratory. Field studies include engineering geological mapping, intensive discontinuity surveying, core drilling, pressurized water tests and sampling for laboratory testing.Uniaxial, triaxial and tensile strength tests were performed and deformation parameters, unit weight and porosity were determined on the intact rock specimens in the laboratory. Rock mass strength and modulus of elasticity of rock mass are determined using the Hoek–Brown empirical strength criterion. Rock mass classifications have been performed according to RMR and Q systems for the diversion tunnel.Engineering geological assessment of the proposed dam and reservoir area indicated that there will be no foundation stability problems. Detailed geotechnical investigations are required for the final design of the dam. 相似文献
6.
Engineering geological studies and tunnel support design at Sulakyurt dam site, Turkey 总被引：2，自引：0，他引：2
H. Basarir 《Engineering Geology》2006,86(4):225-237
This paper presents the results of engineering geological investigations and tunnel support design studies, carried out at the Sulakyurt dam site, northeast of Ankara, Turkey. The Sulakyurt dam will be used for flow control and water storage for irrigation projects. Studies were carried out both in the field and the laboratory. Field studies include engineering geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. The diversion tunnel will be driven in rock mass, consisting of granite and diorite. Empirical, analytical and numerical methods were combined for safe tunnel design. Rock mass rating (RMR), Rock mass quality (Q) and Geological strength index (GSI) systems were used for empirical rock mass quality determination, site characterization and support design. The convergence–confinement method was used as analytical method and software called Phase2, a 2D finite element program, was utilized as numerical method. According to the results acquired from the empirical, analytical and numerical methods, tunnel stability problems were expected in both granite and diorite rock masses. The support system, suggested by empirical methods, was applied and the performance of suggested support system was evaluated by means of numerical modelling. It was concluded that the suggested support systems were adequate, since after applying the suggested support system to granite and diorite, tunnel deformation and the yielded elements around the tunnel decreased significantly. Thus, it is suggested that for more reliable support design empirical, numerical and analytical methods should be combined. 相似文献
7.
施工期围岩快速分级是保证隧道施工安全和工程质量的关键措施。结合绩黄、宁绩高速公路隧道群施工期围岩分级实践,在大量现场测试和室内试验的基础上,提出了一种基于国标BQ分级的新分级体系,并给出了每个分级指标的现场快速测试方法。用新分级体系进行隧道施工期围岩的快速分级工作,并以分级结果作为进化支持向量回归算法分级的训练样本,建立了隧道围岩分级的进化支持向量回归智能模型。为了方便现场使用,依据支持向量回归理论,将智能模型进一步转化为初等函数数学模型,经隧道围岩分级实例验证了该初等函数数学模型的准确性,为隧道施工期围岩快速分级提供了一种简便的新方法。 相似文献
8.
Satish Kumar Kishor Kumar N. N. Dogra 《Journal of the Geological Society of India》2017,89(4):407-412
Rock slopes require geo-engineering evaluation to assess the instability of critical slopes leading to landslides particularly in Himalayan terrain where rocks are highly jointed, fractured and weathering prone. Interplay of discontinuities in the rocks coupled with other parameters is one of the prime causes of failure of slopes. Engineering rock mass classification, such as, rock mass rating (RMR) and slope mass rating (SMR) along with geological strength index (GSI) have widely been used for stability assessment of rock slopes above tunnel portals, and these classifications are employed here for assessment of stability of slopes of critical nature along Rampur-Powari highway in Himachal Pradesh. In the present study, out of 154 numbers of slopes, a total of 29 have been selected for assessment of their criticality by employing RMR, SMR and GSI. 相似文献
9.
隧洞围岩分类与洞径和超欠挖之间的关系研究 总被引：5，自引：0，他引：5
岩体的地质结构特征是影响隧洞围岩超欠挖的主要因素,正确评价岩体的质量,对岩体进行分类,并研究岩体质量与隧洞超欠挖之间的关系对分析和预测隧洞超欠挖具有重要的意义。对隧洞围岩的RMR分类和Q分类与超欠挖之间的关系进行了详细研究,研究了在同类岩体条件下不同开挖洞径与隧洞超欠挖之间的关系,并由此建立了RMR分类和Q分类之间的关系,得出围岩的RMR分类和Q分类与隧洞超欠挖呈线性关系和对数线性关系,根据超欠挖建立起来的RMR分类和Q分类之间的关系比较符合工程实际。最后研究了超欠挖与围岩分类及洞径之间的复相关关系。 相似文献
10.
The results of geotechnical explorations, engineering geological investigation (including laboratory and in situ tests) and
field observations have been used, along with borehole logging charts, to obtain the rock mass geotechnical data. Based on
the data, the rock mass along the Sabzkuh water conveyance tunnel route was classified by rock mass rating (RMR), Q-system
(Q), rock mass index (RMi) and geological strength index (GSI) (3 methods). A new series of correlations were established between
the systems based on the data collected from the study area. These relationships were then compared with those reported in
the literature, and two new relations were recommended. The classifications were utilized to calculate mechanical properties
(rock mass strength and deformation modulus) of the rock mass along the tunnel according to available empirical relations,
and to distinguish the upper-bound and lower-bound relations. 相似文献
11.
The joint frequency rating index accounts for 40% of the weight in the hundred-mark Rock Mass Rating 2014 (RMR14) classification system. However, owning to the natural variations of in-situ rock mass, this parameter is difficult for site engineers to obtain along the tunnel axis, especially in groundwater-rich conditions or prior to any disturbances made to rock mass. In this study, we propose an equivalent joint frequency, expressed quantitatively in terms of the ratio of the P-wave propagation velocity in the rock mass to that of the intact rocks, which is mainly based on engineering statistics easily obtained from the Chinese National Standard, GB/T 50218. We also explore a new rating method, based on field P-wave propagation velocity tests, for the joint frequency in the RMR14 classification system. Literature from in-situ databases is discussed to verify the applicability of the proposed rating method. The verifications demonstrate that, compared with the results of on-site parameters ratings as per the RMR classification system, the new rating method using P-wave propagation velocity can obtain a certain degree of accuracy. Hence, this enables the presentation of the primary state of integrity of an in-situ rock mass in accordance with the RMR14 classification system, through simple and non-destructive field P-wave velocity tests.
相似文献12.
传统的RMR法采用固定评估因素、固定评分方式进行岩体分级,其评分过程中存在着许多不确定性和主观性,在地质条件复杂的情况下岩体分级效果差.为了改变RMR法存在的不足,本文在参考RMR法的基础之上,提出了将AHP法应用于岩体分级的方案,给出了模型计算流程.将岩体分级看作一个多属性决策问题,根据实际情况可随机加入或减少影响岩... 相似文献
13.
Support capacity estimation of a diversion tunnel in weak rock 总被引：4，自引：0，他引：4
This paper presents the results of the support capacity estimation for the diversion tunnel of the Uru
dam site in highly weathered tuff and weak zone. Tunneling in weak rock requires some special considerations, since misjudgment in support design results in costly failures. There are several ways of estimating rock support pressure and selecting support. However, all systems suffer from their characteristic limitations in achieving objectives. Thus, it is more useful to use different methods for estimating support pressure and type of support. The support pressure pi was established by three different methods. These methods are the (1) empirical methods based on rock mass rating (RMR) and rock mass quality index (Q-classification systems), (2) ground support interaction analysis (GSIA) and (3) numerical methods, namely, Phase2 finite element (FEM) program. Rock masses were characterized in terms of RSR, RMR, Q-system and GSI. Drill-core samples were tested in the rock mechanics laboratory to determine physico-mechanical properties. Rock mass strength was estimated by empirical methods. Finally, the required support system is proposed and evaluated by different methods in the highly weathered tuff and weak zone of the diversion tunnel. 相似文献
14.
A. Tu
rul 《Engineering Geology》1998,50(3-4):337-345
The Atatürk dam was built across the Firat River on clayey limestone. A grout curtain, providing impermeability in the left and right abutments, was done in grouting galleries. The well known rock mass classification systems for tunneling purposes [rock structure rating (RSR), rock mass rating (RMR) and rock mass quality index (Q)] were used to classify the rock mass along these galleries. Based on RSR, RMR and Q values, the rock masses in the galleries have been classified into three different classes. Correlation between the three classification systems is discussed and suggestions are made for using rockbolt, shotcrete with wiremesh and steel ribs for supporting the rock mass. 相似文献
15.
ABSTRACT The local site experience is a valuable component for the success of rock mass classification systems as tunnel design methods. The Ituango hydroelectric project is a very important source of information in order to evaluate the usefulness of the main rock mass classification systems. The objective of this research is to improve understanding of some important features of excavated rock mass, such as discontinuities, block size, shear strength and joint alteration, by analyzing some hundreds of data obtained during excavation cycle. The field study included a survey of exposures after drilling and blasting rounds. Rock mass classification and support measures for each type of terrain along 1400 m tunnel were performed. The rock mass classes could be better explained if shear strength, alteration or block size is calculated. The assessment of these data allows evaluating the block fall risk, improving support and liner. A local correlation between the RMR and Q system was also obtained. 相似文献
16.
Influence of Rock Mass Parameters on the Performance of a TBM in a Gneissic Formation (Varzo Tunnel) 总被引：4，自引：1，他引：4
Summary The paper analyses the influence of rock mass quality on the performance of a double shield TBM in the excavation of a tunnel in a gneiss formation which is characterized by high strength and low fracture intensity.As full observation of the rock conditions was prevented by the use of segmental lining, a geomechanical survey of the face was performed during maintenance downtime and the observed conditions were correlated with the machine performance parameters for that same day. A statistical analysis of the data shows that penetration rate correlates well with a slightly modified RMR index (in which the influence of the water conditions and joint orientation were discounted), but the most important factor is by far the partial rating of the RMR classification related to joint spacing only. However in tunnels characterized by greater variability in rock strength and joint conditions, it could be worthwhile using the complete RMR index.Given the toughness of the rock, failure of the cutter bearings and supports were a frequent occurrence during excavation. Owing to this factor the influence of rock quality on the rate of advance was found to be weak and the correlation more scattered.The results obtained for the Varzo tunnel were compared with those relative to other tunnels in granitic rocks and found to be in good agreement. However the relationships obtained should be considered valid only for this type of rock; machine behaviour could be found to be markedly different in other rock types, even where rock material strength and joint frequency are the same. 相似文献
17.
施工期隧道岩体质量动态分级,是评价隧道工作面围岩质量最直接的方法,也是预防隧道施工地质灾害,决定施工开挖工法与支护措施的重要依据。由于传统的Q值法和国标BQ岩体质量分级评价方法需要进行现场和室内试验及分析,岩体质量评价时间滞后,常常降低施工效率,或错过预防突发性施工地质灾害的窗口时间,快速准确地对隧道工作面进行岩体质量分级,成为施工期公路隧道岩体质量动态分级需要解决的重要问题。人工智能算法为解决隧道岩体质量实时快速准确评价提供了方法和手段。以北京冬奥会延庆—崇礼高速公路为例,提出了工作面采用隧道掌子面图片人工智能岩体结构参数辨识,建立7个指标参数体系,采用KNN智能算法对隧道岩体质量进行评价,选取8条隧道40个工作面150个样本进行训练学习,另外选取50个样本进行岩体质量评价校验,与BQ岩体质量评价结果相比,准确率达到了90%,得出如下结论:(1)公路隧道岩体质量智能动态分级KNN方法—一种利用人工智能技术快速高效进行岩体质量动态分级的方法,能够在现场实时获得岩体质量评价结果;(2)KNN分级方法中选用了7个判定指标,综合考虑了隧道围岩体的赋存环境、岩体构造、地质结构等特性,并体现了这些指标在实际工程评判中的可操作性和适用性;(3)KNN分级方法误判率很低,在判别分类中排除了评分时人为因素的干扰,具有较强的判别能力,为TBM围岩实时分级做方法储备。 相似文献
18.
The competency of any TBM in any geological condition is determined by a rock or rock mass breakage process. A 12.24 km long tunnel between Maroshi and Ruparel College was excavated by Brihanmumbai municipal corporation (BMC) to improve water supply system of greater Mumbai, India, using open-type hard rock tunnel boring machines (TBMs). In this paper an attempt has been made to establish the relationship between rock mass characteristics i.e. RMR and UCS of the Deccan trap rocks and TBMs performance characteristics for 5.83 km long Maroshi–Vakola tunnel section of the Maroshi–Ruparel college tunnel project. To analyze the effect of variable rock mass conditions on the TBM performance, the operating parameters i.e. thrust force, torque and RPM of the machine, were recorded and intact rock strength was determined. The effect of rock mass properties on machine penetration rate (PR) and the relation with other operational parameters were analyzed. The rock strength affects the rock behaviour under compression. When the rolling cutters indent the rock, the stress exerted must be higher than the rock strength i.e.; the rock strength is directly relevant to the performance of TBM. Studies show that the penetration rate decreases with increase in uniaxial compressive strength (UCS). The comparison of measured penetration rate with empirical model developed by Graham, in which, the penetration rate is computed using UCS and average thrust per cutter, showed good agreement with coefficient of determination (R2), i.e. 0.97. The study shows that the TBM performance was maximum in rock mass rating (RMR) range from 40 to 75, while slower penetration was recorded both in very poor and very good rock masses. 相似文献
19.
Faisal I. Shalabi Husam A. Al-Qablan Omar H. Al-Hattamleh 《Geotechnical and Geological Engineering》2009,27(2):237-248
Lining contact pressure and ground deformation of Raghadan transportation tunnel (Amman, Jordan) were investigated. The tunnel
is 1.1 km in length and 13.5 m in diameter. This study was intended to integrate useful relations among the widely used rock
classification system (RMR: rock mass rating), Hoek–Brown classification, and lining-ground interaction. The materials encountered
along the tunnel alignment were limestone, dolomatic limestone, marly limestone, dolomite, and sillicified limestone. The
ground conditions along the tunnel alignment including bedding planes, joint sets and joint conditions, rock quality, water
flow, and rock strength were evaluated based on the drilled boreholes and rock exposures. Elasto-plastic finite element analyses
were conducted to study the effect of rock mass conditions and tunnel face advance on the behavior of lining-ground interaction.
The results of the analyses showed that lining contact pressure decreases linearly with the increase in RMR value. Also the
results showed that tunnel lining contact pressure and crown inward displacement decreases with the increase in the unsupported
distance (distance between tunnel face and the end of the erected lining). Ground displacement above the tunnel crown was
found to be increases in an increasing rate with the decrease in the depth above the crown. This displacement was also found
to be affected by the RMR value and the unsupported distance. 相似文献
20.
Systematic rock mass characterization is an integral part of rock engineering practices. In the present scenario several classifications
are in used for rock mass characterization for tunnelling. The present paper discusses engineering geological investigations
carried out for Punasa tunnel, a part of Narmada Sagar project. The horse shoe shaped tunnel is 3675.25 m long and 9 m in
diameter. This straight and free flow tunnel has been constructed in basaltic lava flows erupted during Cretaceous to Eocene
age, belonging to poor to fair rock mass rating (RMR) and extremely poor to good in tunnel quality (Q-system). The values
of RMR and Q-system ranges from 29 to 74 and 0.0825 to 13.33 respectively. 相似文献