The performance prediction of impact hammers from Schmidt hammer rebound values in Istanbul metro tunnel drivages

The construction of the first metro line in Istanbul was realized between Galata and Beyoglu by a French Engineer Henry Gavand in January 1875. Six different metro projects were submitted since then to the Turkish authorities. The construction of 7-km metro tunnels phase 1 started in 1992 and the metro line of the phase 1 is opened to the service in 2000. The tunnels of the phase 2 between Taksim and Yenikapi are under construction. This paper summarizes the construction methods of the Istanbul metro tunnels, the performance of the impact hammers, the factors effecting daily advance rates and the previous studies on Schmidt hammer test and performance prediction of impact hammers. At the end, a prediction model concerning instantaneous breaking rates of hydraulic impact hammers from Schmidt hammer rebound values is explained in detail.     

ANN and ANFIS performance prediction models for hydraulic impact hammers

Hydraulic impact hammers are mechanical excavators that can be used in tunneling projects economically under geologic conditions suitable for rock breakage by indentation. However, there is relatively less published material in the literature in relation to predicting the performance of that equipment employing rock properties and machine parameters. In tunnel excavation projects, there is often a need for accurate prediction the performance of such machinery. The poor prediction of machine performance can lead to very costly contractual claims. In this study, the application of soft computing methods for data analysis called artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) to predict the net breaking rate of an impact hammer is demonstrated. The prediction capabilities offered by ANN and ANFIS were shown by using field data of obtained from metro tunnel project in Istanbul, Turkey. For this purpose, two prediction models based on ANN and ANFIS were developed and the results obtained from those models were then compared to those of multiple regression-based predictions. Various statistical performance indexes were used to compare the performance of those prediction models. The results suggest that the proposed ANFIS-based prediction model outperforms both ANN model and the classical multiple regression-based prediction model, and thus can be used to produce a more accurate and reliable estimate of impact hammer performance from Schmidt hammer rebound hardness (SHRH) and rock quality designation (RQD) values obtained from the field tests.     

Predicting performance of impact hammers from rock quality designation and compressive strength properties in various rock masses

Predicting the performance of the impact hammers is one of the major subjects in determining the economics of the underground excavation projects in which they are utilized. Therefore, researchers have been attracted to developing performance prediction models for these machines. Physical and mechanical properties of rocks have been used to estimate the performance of impact hammers over the last few decades. In this study, the instantaneous breaking rate (IBR, m³/h) of an impact hammer used in construction of Levent-Hisarüstü metro tunnel (Istanbul) is recorded in detail. Sixty rock samples are obtained from tunnel route during the excavation of which the machine is employed. Physical and mechanical property tests are performed on the obtained samples. A data set including uniaxial compressive strength (UCS), rock quality designation index (RQD), Brazilian tensile strength (BTS), density (ρ), Schmidt hammer hardness (SHH), Shore scleroscope hardness (SSH), Cerchar abrasivity index (CAI), and IBR is formed. Regression analysis techniques are applied to the created data set in order to develop a performance prediction model. The investigation results in a model that can predict IBR based on UCS, RQD, and the output power of the impact hammer. The proposed model passes both F-test and t-test at 0.95 confidence level. The soundness of the model is successfully tested against two formerly developed models. Covering a wide range of application and requiring only two of the most common and versatile rock properties as input parameters are the other advantages of the suggested model.     

Comparative studies on the performance of a roadheader,impact hammer and drilling and blasting method in the excavation of metro station tunnels in Istanbul

Drilling and blasting is the most widely used excavation method in mining and tunnelling especially in hard rock conditions. But in recent years, the application of roadheaders and impact hammers in hard rock, especially in fractured geological formations has increased considerably. However, it is strongly emphasized that the prediction of the machine performance plays an important role in the time scheduling and in the economy of tunnelling projects and accumulated data will serve a sound basis for performance prediction models.This paper presents information on Istanbul Kadikoy–Kartal metro tunnels which are planned to be constructed in two stages, the first one which is in Kozyatagi–Kadikoy direction and the second in Kozyatagi–Kartal direction. The construction method of the Kozyatagi–Kadikoy station tunnels is first summarized and later, the performance of a roadheader, impact hammer and the results of drilling and blasting methods are compared.The results of this study show that machine utilization time is 28.2% for roadheader and 14.2% for impact hammers. Average net cutting rates (NCR) are 32.26 m³/h for roadheader (218.3 m³/day), net breaking rate (NBR) 13.1 m³/h (45 m³/day) for impact hammers and production rate with drill and blast method (D&B) is found to be 187 m³/day.     

新型液压破碎锤的研究

在分析国内外现有液压破碎锤工作原理的基础上首次提出一种可以无级调节冲击能和冲击频率的新型液压破碎锤，并对它进行了计算机仿真研究，同时通过样机进行了大量的实验研究。实践证明，该液压破碎锤具有结构简单、冲击能和冲击频率可无级调节，节能，维修方便等优点。     

Safe distance to foundations when compacting soil in the channels by hydraulic hammers

Results are presented for experimental studies conducted on models and full-scale foundations to evaluate the influence exerted by the operation of hydraulic hammers on foundation stability during the compaction of soil. Recommendations are given for safe distances to foundation walls when soil is compacted in the foundation channels with allowance for the impact energy of the hydraulic hammer. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 16–20, September–October, 1997.     

中国液压破碎锤行业的进步与不足

论述了近5年以来,我国液压破碎锤在生产制造、市场销售、行业标准、行业组织、咨询服务等方面的巨大进步,也具体指出行业存在的问题与不足之处。     

特殊条件下大型水闸的拆除

对于高架桥梁,将其支座破除使其坠落到地面或将其分解吊到地面再用液压破碎锤破碎,施工方便、安全;对于墩墙及布筋密、强度高的混凝土,先用膨胀剂将其胀裂,再用液压破碎锤破碎,速度快;对布筋少、强度低的底板混凝土,直接用液压破碎锤破拆,节省费用;闸底粗大木桩先开挖部分桩间土,才能用50 t履带式起重机拔出。采用这些非爆破法拆除旧闸,可满足水阐拆除特殊要求。     

Prediction of the performance of impact hammer by adaptive neuro-fuzzy inference system modelling

Impact type excavators are widely used for excavations, performed in weak-laminated-foliated-anisotropic rocks. Therefore the prediction of the performance of impact hammer is very important in many mining and civil engineering projects.This paper describes the construction of adaptive neuro-fuzzy inference system model for predicting the performance of impact hammer type excavator by considering rock and excavating machine properties such as block punch strength index, geological strength index system and impact hammer power. Extensive field and laboratory studies were conducted in the tunnel construction route of the second stage of Izmir Metro Project, which excavated in laminated-foliated flysch rocks. The results of the constructed adaptive neuro-fuzzy inference system and traditional multiple regression models were compared. Although the prediction performance of traditional multiple regression model is high, it is seen that adaptive neuro-fuzzy inference model exhibits better prediction performance according to statistical performance indicators. By means of the developed model, the performance of impact type excavators can be predicted in terms of net excavation based on the selected rock and machine properties.     

液压气动复合锤工作过程分析

分析某型液压气动打桩锤的液压回路,建立上升和下降过程的动力学方程,分析主要参数对液压锤工作性能的影响,得到了一组符合设计条件的参数,计算结果对液压锤的设计开发具有指导作用。     

填石路基动力夯实离散元数值分析

本文意在使用数值计算方法分析填石路基动力夯实效果及施工设备参数优化问题。以液压夯实技术为例,基于碎石土孔隙率的变化使用二维颗粒流离散元方法对填石路基动力夯实问题进行计算分析。基于夯击前后填石材料孔隙率的改变,讨论了不同夯锤重量、不同夯锤下落高度及不同夯锤提升时间3种情况下路基的动力夯实效果及动力夯击的有效影响深度。由计算结果的对比分析可知,增大夯锤重量和提高落锤高度均可有效增强动力夯实效果及增大夯击的影响深度;增大提锤时间只能小幅提升填石路基的动力夯实效果,而对动力夯击的有效影响深度影响不大。液压夯实技术适合选用改变锤重方案来增强动力夯实效果以及增大夯击的影响深度。     

Indian experiences with Q and RMR systems

The Q-systemir of Barton et. al. (1974, 1976) and the RMR-system of Bieniawski (1973) have been evaluated on the basis of measured tunnel support pressures from 26 tunnel sections, 2 to 14 m wide, covering both squeezing and non-squeezing ground conditions. The comparison shows that the Q-system is unsafe for large tunnels under squeezing ground conditiona. A new correlation has been developed considering tunnel depth, tunnel radius, tunnel closure, and Rock Mass Number—i.e., “stress free Q”—to obtain reliable estimates of tunnel support pressures. Changes suggested by Sheorey (1991) for satisfactory application of the Q system to coal-mine roadways on the basis of 44 case histories are presented. Unal's (1983) correlation for coal-mine roadways is shown as overly safe for large tunnels under non-squeezing ground conditions, and unsafe for all sizes of tunnels under squeezing ground conditions. Correlations between tunnel support pressure, tunnel depth, tunnel closure, and Bieniawski's RMR have been developed to provide reliable tunnel support pressures for all sizes of rock tunnels under varying ground conditions. The correlations between RMR and Q proposed by Bieniawski (1976) and by Rutledge and Preston (1978) are not reliable, because RMR and Q are not truly equivalent. Therefore, an acceptable correlation between rock mass number N and RMR_mod, i.e., RMR without joint orientation and intact rock strength, has been presented for a better interrelation.     

Driven cast-in-situ piles installed using hydraulic hammers: Installation energy transfer and driveability assessment

The ability of hydraulic pile driving hammers to overcome energy losses during freefall enables a greater proportion of the impact energy to be transferred to the pile than is possible with diesel hammers. This percentage, termed the energy transfer ratio, is not routinely measured in practice however, and there is an element of uncertainty regarding appropriate energy transfer ratios to adopt in driveability analyses. In light of such uncertainties, the energy transfer ratios of four- and five-tonne hydraulic hammers were assessed during installation of driven cast-in-situ (DCIS) piles at several sites in the United Kingdom. The piling rigs were fitted with instrumentation enabling the hammer velocity (and hence kinetic energy) at impact to be inferred for each blow during installation, with the corresponding energy transferred to the closed-ended steel installation tube ascertained using a Pile Driving Analyzer. The results of the study showed that energy transfer ratios were strongly dependent on the hammer drop height, with transfer ratios of 90% and above only achievable for drop heights in excess of 50% of the maximum value. Driveability analyses using measured energy transfer ratios from the fieldwork, as well as the traditional method using an assumed energy transfer ratio which is independent of drop height, yielded good agreement with measured driving records at a clean sand site. In contrast, poorer predictions were apparent for both methods at another site, where the coarse-grained strata had higher fines contents and significant layering, with the traditional method (assumed energy transfer ratio) over-predicting the maximum transferred energy and concealing the influence of dynamic soil properties on driveability. The findings of the study would suggest that lower energy transfer ratios may need to be considered in driveability predictions for these pile types (i.e. steel or DCIS piles) if lower drop heights are used during driving.     

液压桩锤液压系统

液压桩锤诸多的优点使其被称为有发展前途的桩工机械。为此作者从液压桩锤液压系统的基本回路、油路连接基本原则、液压元件选择等方面对其进行了系统的介绍，并分析了几种典型液压桩锤液压回路的主要特点。     

新型压力反馈式液压锤的试验研究

针对一种新型压力反馈式液压锤进行试验研究。试验结果表明:改变液压锤相关的工作参数,可以实现独立调节冲击能和冲击频率的功能,验证了该种控制方案理论的可行性,并对试验结果进行了详细分析总结,为深入了解其运动规律提供了依据。     

Blast performance in small tunnels - a critical evaluation in underground metal mines

Tunnels can be classified by size as small, medium or large. Blast design parameters and blast performance are considerably influenced by tunnel size. Though parallel cut is more suitable for a higher advance in small drivages, wedge cut proved to be more productive than parallel cut in the small drivages of a manganese mine (no. 1) because of the need for greater charge and more holes per unit of cut area. A double wedge cut pattern is suggested èfor improved blast results in these drivages. Analyses of blast results in around 600m of small rectangular tunnels driven in the host rock and the ore body of two metal mines led to development of an empirical relation for precise prediction of powder factor and specific drilling with wedge cut and parallel cut considering rock strength parameter, Q and hole depth.     

An appraisal of TBM performances in Turkey in difficult ground conditions and some recommendations

The geology of Turkey is very complex and major Northern and Eastern Faults including minor faults associated to these faults create tremendous problems, like squeezing of the TBM, excessive water ingress, TBM face collapses, as encountered in the Kargi power tunnel, the Dogancay energy tunnel, the Gerede water tunnel, and the Nur Dagi railway tunnel. Mixed ground conditions with ophiolites, graphitic schists and melanges with boulders are other fundamental difficulties leading to squeezing and blocking of the TBMs or even causing complete failures of the segments and abandoning of the tunnel. A typical example for tunnel abandoning is the Kosekoy high speed tunnel and an example for excessive TBM squeezing is the Uluabat energy tunnel. The affects of dykes in the Istanbul region is known well by practicing tunnel engineers. These andesitic rocks, make fractures in the country rock and cause several problems during TBM excavation like blocking the cutterhead and excessive disc cutter consumption. Typical examples are the Goztepe-Kadıkoy Metro tunnels, and the Melen water tunnel. The Beykoz utility tunnel is one of the most difficult tunnelling projects in Istanbul. Presence of clay minerals existing within the geologic formations is also one of the main reasons clogging the cutterhead of TBM as encountered in the Suruc water project. The effects of complex geology on the excavation efficiencies of different type of TBM’s used in the ten projects mentioned above are explained in this paper and some recommendations with a ground classification system for proper use of TBMs in faultyzones are given.     

台灣水利隧道工程TBM開挖首次貫通案例

新武界隧道及栗栖溪引水工程之隧道總長約16.5km,興建完成後將為台灣最長之水利隧道。其中,中游段之引水隧道艮約7.8km,因推估地質均質尚佳且無明顯之剪裂帶或斷層带存在,並為考慮縮短工期、降低對環境之衝擊、減少勞工需求及提昇台灣隧道工程施工技術等因素,決定採用安全且一貫連續快速作業之隧道鑽掘機(TBM)開挖施工。施工期間,於2001年11月份創下659.3m／月之台灣最快鑽掘紀錄,其後雖曾遭遇局部岩盤破碎或異常擠壓等不良地質,以及遭受桃芝颱風之暴雨肆虐成災,然於採取適當應變措施及處理得宜下,TBM終於克服困難並持續順利鑽掘,且於2002年6月7日成功貫通,完成鑽掘工作,為台灣隧道工程首次以TBM貫通案例,且達到最佳平均月進度(315m/月)及最大鑽掘長度(6523m)之新里程碑。     

新型液压冲击机械控制系统方案研究

不管是液压凿岩机还是液压破碎锤,必须有各种性能完善的液压钻车或液压挖掘机与其配套,才能完成应有的工作机能。液压控制系统的主要功能是：控制液压冲击器的工作;控制液压支臂的变幅运动及回转运动以便使冲击器对准要破碎的物体;驱动行走机构等。笔者结合多年的新型液压冲击机械的操作经验提出了相应的控制系统方案研究,希望通过对该方案的研究促进我国建设施工工作中新型液压冲击机械控制系统的推广和完善。     

Geostatistical assessment of rock zones for tunneling

Geostatistical assessments can be used for understanding the distribution of regionalized variables (ReVs) in any spatial study. Many researchers have used the theory of ReVs for different modeling purposes such as hydraulics, mining deposits, etc. In this paper, ReV technique is used for understanding the mechanical variation properties of rock zones under sampled and unsampled conditions in sewer tunnels for Istanbul. This study has been carried out for three different rock properties that are compressive strength, rock quality designation (RQD), Schmidt hammer hardness, and one rock cuttability property, net cutting rate. In order to define ReVs distribution, first semivariogram functions are determined and then kriging maps are generated for identifying the regional dependence. Furthermore, it is possible to make estimations for every point within the study area, and prepare maps for the interpretation of regional features of the ReV concerned. Net cutting rate is a cuttability property of rock, which can be regionalized and compared with the mechanical properties of rocks. This can be used for predicting the performance of excavator.