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TBM penetration rate prediction based on the long short-term memory neural network

Underground Space 2021年第6期6卷 718-731页

作者： Boyang Gao RuiRui Wang Chunjin Lin Xu Guo Bin Liu Wengang Zhang Geotechnical and Structural Engineering Research Center Shandong UniversityJinanChina School of Qilu Transportation Shandong UniversityJinanChina School of Civil Engineering Shandong UniversityJinanChina Data Science Institute Shandong UniversityJinanChina Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqingChina National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqingChina School of Civil Engineering Chongqing UniversityChongqingChina

Tunnel boring machines(TBMs)are widely used in tunnel engineering because of their safety and efficiency.The TBM penetration rate(PR)is crucial,as its real-time prediction can reflect the adaptation of a TBM under current geological conditions and assist the adjustment of operating parameters.In this study,deep learning technology is applied to TBM performance prediction,and a PR prediction model based on a long short-term memory(LSTM)neuron network is proposed.To verify the performance of the proposed model,the machine parameters,rock mass parameters,and geological survey data from the water conveyance tunnel of the Hangzhou Second Water Source project were collected to form a dataset.Furthermore,2313 excavation cycles were randomly composed of training datasets to train the LSTM-based model,and 257 excavation cycles were used as a testing dataset to test the performance.The root mean square error and the mean absolute error of the proposed model are 4.733 and 3.204,respectively.Compared with Recurrent neuron network(RNN)based model and traditional time-series prediction model autoregressive integrated moving average with explanation variables(ARIMAX),the overall performance on proposed model is better.Moreover,in the rapidly increasing period of the PR,the error of the LSTM-based model prediction curve is significantly smaller than those of the other two models.The prediction results indicate that the LSTM-based model proposed herein is relatively accurate,thereby providing guidance for the excavation process of TBMs and offering practical application value.

关键词： TBM performance prediction penetration rate Long short-term memory Water conveyance tunnel

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Observation on Sperm penetration rate of Infertile Men with Varicocele at 1.5 to 2 Years after Varicolectomy

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Journal of Reproduction and Contraception 2002年第1期13卷 10-15页

作者：梁蔚波朱伟杰苏泽轩 Department of Urology the First Affiliated Hospital of Medical College Jinan University Guangzhou 510632 China Center for Reproductive Immunology Research Jinan University Guangzhou 510632China

Objective To observe the sperm penetration rate among treated but 'unsuccessful' infertile men with varicocele Material & Methods Twenty nine infertile males with II°(n=17) or III°(n=12) varicocele were enrolled into this study. They underwent a varicolectomy, but their spouses had not achieved a pregnancy after 1.5~2 years of treatment. The sperm zona-free hamster oocyte penetration assay (SPA) was used to compare the sperm penetration rate (PR) before treatment and 1.5~2 years after treatment. Results After varicolectomy, enhanced PR were observed in 7 cases of the II°group and in 1 case of the III°group. However, the PR values of these 8 cases were still below 20% PR-level. Conclusion Among the treated but 'unsuccessful' men, some patients could obtain improvements on PR after varicolectomy. But PRs of men with III°grade varicele would still remain a low PR-level which indicate varicolectomy is ineffective in increasing PR among part of sever varicocele patients. SPA is a useful test for evaluating the fertilizing potential of treated infertile males with varicocele.

关键词： varicocele zona-free hamster oocyte penetration assay(SPA) sperm penetration rate

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Improving TC drill bit's efficiency and resistance to wear by graphene coating

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Petroleum Research 2022年第4期7卷 430-436页

作者： Reza Taheri Mohsen Jalali Ahmed Al-Yaseri George Yabesh Petroleum Engineering Department University of WyomingWYUSA Petroleum Engineering Department Tehran Azad UniversityTehranIran Petroleum Engineering Discipline Engineering SchoolEdith Cowan UniversityAustralia

Displaying a two-dimensional pure crystal carbon structure,Graphene is the strongest,yet thinnest substance discovered by scientists.Coating tungsten carbide(TC)drill bits with graphene to evaluate the effect of graphene on the wear,as well as the rate of penetration of the drilling bit was examined in this research.Two evaluation approaches were employed:one with employing ANSYS Software and the second by employing atomic pressure chemical vapor deposition(APCVD synthesis)in the laboratory to produce a monolayer graphene coating.The simultaneous software-based and lab-based testing were performed to increase the credibility of the results and minimize the potential errors.Conducting the simulation using ANSYS,the maximum shear elastic strain,equivalent elastic strain,equivalent(von mises)stress,total deformation and maximum shear stress were investigated prior and after the gra-phene coating was applied on TC simulated bit.Total deformation was only slightly increased,while the maximum shear elastic strain was almost doubled,reflecting that the bit's wear was significantly reduced after the coating.Lab-based APCVD synthesis results showed 34%increase in compressive strength of the coated bit,in comparison to the uncoated one.The failure occurred for uncoated bit at 35 MPa,where the coated bit experienced failure at 46.9 MPa.The Von Mises stress test conducted on the coated and uncoated samples also indicated that this stress was 41%less for the coated bit,in comparison to the uncoated one.Finally,two small-scale drilling operations,one using a 1inch graphene-coated TC bit and the other using a 1inch non-coated TC bit,were performed on a granite block,to evaluate the performance of the graphene-coated bit in practice.In a chosen 120-min time frame,27 consecutive holes could be drilled by the graphene-coated TC bit,while 19 consecutive holes could be drilled by the uncoated TC bit,in identical drilling conditions.This implies a 42%increase in ROP.

关键词： Drill bit's efficiency Graphene-coated ANSYS APCVD Wear reduction penetration rate

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Analysis of Power Quality Problems in Large-Scale Application of Air-Source Heat Pump

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Energy Engineering 2022年第2期119卷 637-651页

作者： Zhihao Zheng Yanbo Che Hailian Bi Dan Wu Wei He Key Laboratory of Smart Grid of Education Ministry Tianjin UniversityTianjin300072China Electric Power Science Research Institute of State Grid Jiangxi Electric Power Co. Ltd.Nanchang330096China

With the implementation of electric energy alternatives,the large-scale application of electric energy substitution represented by air-source heat pumps has replaced traditional coal-fired heating,which is beneficial for the environment and alleviates air pollution.However,the large-scale application of airsource heat pumps has brought power quality problems such as voltage sags,harmonic pollution,and three-phase imbalance to the distribution network.This paper studies the fixed-frequency and variablefrequency air-source heat pump,introduces its working principle,analyzes the mechanism of its power quality problem.Moreover,the paper establishes a simulation model for the fixed-frequency heat pump and variable-frequency heat pump to connect to the distribution network.This research mainly studies the impact of large-scale fixed-frequency heat pumps on the depth of voltage sags in the distribution network and the impact of large-scale variable-frequency heat pumps on the harmonic content of the distribution network under different penetration rates and uses measured data to verify the reliability of the simulation results.This paper uses experimental data for the first time to verify the real power quality problems of large-scale heat pumps,which can provide a reference for determining the power quality standards for heat pumps connected to the power grid.At the same time,it can also provide a reference for the power quality management of the distribution network that is actually connected to electric heating.

关键词： Air-source heat pump voltage sag harmonic penetration rate

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Hard rock tunnel boring machine penetration test as an indicator of chipping process efficiency

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 611-622页

作者： M.C. Villeneuve Department of Geological Sciences University of Canterbury Christchurch 8140 New Zealand

The transition from grinding to chipping can be observed in tunnel boring machine(TBM) penetration test data by plotting the penetration rate(distance/revolution) against the net cutter thrust(force per cutter) over the full range of penetration rates in the test.Correlating penetration test data to the geological and geomechanical characteristics of rock masses through which a penetration test is conducted provides the ability to reveal the efficiency of the chipping process in response to changing geological conditions.penetration test data can also be used to identify stress-induced tunnel face instability.This research shows that the strength of the rock is an important parameter for controlling how much net cutter thrust is required to transition from grinding to chipping.It also shows that the geological characteristics of a rock will determine how efficient chipping occurs once it has begun.In particular,geological characteristics that lead to efficient fracture propagation,such as fabric and mica contents,will lead to efficient chipping.These findings will enable a better correlation between TBM performance and geological conditions for use in TBM design,as a basis for contractual payments where penetration rate dominates the excavation cycle and in further academic investigations into the TBM excavation process.

关键词： penetration rate Grinding Chipping Geological characteristics Face stability

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Evaluation of boring machine performance with special reference to geomechanical characteristics

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 615-619页

作者： K. Goshtasbi M. Monjezi P. Tourgoli Faculty of Engineering Tarbiat Modares University

The duration of tunneling projects mostly depends on the performance of boring machines. The performance of boring machines is a function of advance rate, which depends on the machine characterizations and geomechanical properties of rock mass. There were various theoretical and empirical models for estimating the advance rate. In this paper, after determining the geomechanical properties of rock mass encountered in the Isfahan metro tunnel, the performance of the roadheader and tunnel boring machine （TBM） were then evaluated using various models. The calculation results show that the average instantaneous cutting rate of the roadheader in sandstone and shale are 42.8 and 74.5 m^3/h respectively. However the actual values in practice are 34.2 and 51.3 m^3/h. The operational cutting rate of the roadheader in sandstone and shale are 8.2 and 9.7 m^3/h respectively, but the actual values are 6.5 and 6.7 m^3/h. The penetration rate of the TBM in shale is predicted to be 50-60 mm/round.

关键词： performance prediction roadheader cutting rate specific energy tunnel boring machine penetration rate

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Heterogeneous traffic flow modeling with drivers’ timid and aggressive characteristics

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Chinese Physics B 2021年第10期30卷 219-230页

作者：翟聪巫威眺罗淞文 School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510641China School of Transportation and Civil Engineering and Architecture Foshan UniversityFoshan 528000China

The driver’s characteristics(e.g.,timid and aggressive)has been proven to greatly affect the traffic flow performance,whereas the underlying assumption in most of the existing studies is that all drivers are homogeneous.In the real traffic environment,the drivers are distinct due to a variety of factors such as personality characteristics.To better reflect the reality,we introduce the penetration rate to describe the degree of drivers’heterogeneity(i.e.,timid and aggressive),and proceed to propose a generalized heterogeneous car-following model with different driver’s characteristics.Through the linear stability analysis,the stability conditions of the proposed heterogeneous traffic flow model are obtained based on the perturbation method.The impacts of the penetration rate of drivers with low intensity,the average value and standard deviation of intensity parameters characterizing two types of drivers on the stability of traffic flow are analyzed by simulation.Results show that higher penetration of aggressive drivers contributes to traffic flow stability.The average value has a great impact on the stability of traffic flow,whereas the impact of the standard deviation is trivial.

关键词： heterogeneous car-following model driver characteristic penetration rate stability

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Drilling cost optimization in a hydrocarbon field by combination of comparative and mathematical methods

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Petroleum Science 2009年第4期6卷 451-463页

作者： A.Bahari A.Baradaran Seyed Iranian Central Oil Fields Company(ICOFC) Esfandiari St.Valiasr Ave. Behinkav Zharfa Consulting Engineers No.45Block 18Phase 2EkbatanTehranIran

In drilling operation, a large saving in time and money would be achieved by reducing the drilling time, since some of the costs are time-dependent. Drilling time could be minimized by raising the penetration rate. In the comparative optimization method, by using the records of the first drilled wells and comparing the criteria like penetration rate, cost per foot and specific energy, the drilling parameters of the next wells being drilled can be optimized in each depth interval. In the mathematical optimization technique, some numerical equations to model the penetration rate, bit wear rate and hydraulics would be used to minimize the drilling cost and time as much as possible and improve the results of the primary comparative optimization. In this research, as a case study the Iranian Khangiran gas field has been evaluated to optimize the drilling costs. A combination of the mentioned optimization techniques resulted in an optimal well which reduced the drilling time and cost considerably in comparison with the wells already drilled.

关键词： Optimization cost per foot penetration rate drilling performance

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Analysis of highway performance under mixed connected and regular vehicle environment

Journal of Intelligent and Connected Vehicles

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Journal of Intelligent and Connected Vehicles 2021年第2期4卷 68-79页

作者： Zhao Zhang Xianfeng(Terry)Yang Department of Civil and Environmental Engineering University of UtahSalt Lake CityUSA

Purpose–This study aims to study the connected vehicle(CV)impact on highway operational performance under a mixed CV and regular vehicle(RV)environment.Design/methodology/approach–The authors implemented a mixed trafﬁcﬂow model,along with a CV speed control model,in the simulation environment.According to the different trafﬁc characteristics between CVs and RVs,this researchﬁrst analyzed how the operation of CVs can affect highway capacity under both one-lane and multi-lane cases.A hypothesis was then made that there shall exist a critical CV penetration rate that can signiﬁcantly show the beneﬁt of CV to the overall trafﬁc.To prove this concept,this study simulated the mixed trafﬁc pattern under various conditions.Findings–The results of this research revealed that performing optimal speed control to CVs will concurrently beneﬁt RVs by improving highway capacity.Furthermore,a critical CV penetration rate should exist at a speciﬁed trafﬁc demand level,which can signiﬁcantly reduce the speed difference between RVs and CVs.The results offer effective insight to understand the potential impacts of different CV penetration rates on highway operation performance.Originality/value–This approach assumes that there shall exist a critical CV penetration rate that can maximize the beneﬁts of CV implementations.CV penetration rate(the proportion of CVs in mixed trafﬁc)is the key factor affecting the impacts of CV on freeway operational performance.The evaluation criteria for freeway operational performance are using average travel time under different given trafﬁc demand patterns.

关键词： Connected vehicle Highway capacity Mixed trafﬁc penetration rate Variable speed limit Paper type Research

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Evaluation of Limestone Interval in the Drilled Surface Section of Bn-1 Oil Well

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Engineering（科研） 2016年第8期8卷 515-524页

作者： Ali K. Darwesh Thorkild Maack Rasmussen Nadhir Al-Ansari Department of Civil Environmental and Natural Resources Engineering Lulea University of Technology Lulea Sweden

The first exploration oil well in any oil block consumes in general more time and cost than the other wells in the same block. Evaluating the drilled wells serves to improve the future operations. This paper evaluates the drilled surface section through real field data for the first exploration oil well drilled in one of the oil blocks, in Kurdistan north of Iraq. The surface section of the well was drilled with the conventional method to penetrate many different geological formations with tight intervals. Drilling efficiency and the difficulties encountered are discussed and explained using various data sources. All daily drilling reports concerning a specific interval were studied. This includes weight on bit, string rotation, mud pump flow and penetration rate. Evaluation was carried out by analyzing the used controllable drilling parameters with the formations features. penetration of the Pila Spi formation (Middle Eocene) was the most difficult formation in the drilled section. Microsoft Office 365 Pro Plus used in making graphs and Excel tables. Evaluations showed that the conventional technology used left many negative effects, like increase in None Productive Time NPT, cost and ground water pollution. Simultaneous Casing Drilling method proposed as an alternative method for the future campaign.

关键词： Oil Exploration Drilling Casing Torque penetration rate Formation Spud

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