外文翻譯=水平定向鉆機障礙檢測傳感器運行建模=4000字符

附錄：翻譯原文 Modeling of an obstacle detection sensor for horizontal directional drilling (HDD) operations A.P. Jaganathan a, J.N. Shah a, E.N. Allouche a, M. Kieba b, C.J. Ziolkowski b Keywords: Look-ahead； Numerical modeling； Differential impedance； Obstacle detection； Horizontal directional drilling Abstract: Horizontal Directional Drilling (HDD) is a commonly used construction method for the installation of underground pipelines, conduits and cables in urban areas and across obstacles such as rivers, railways and highways. A key concern in using the HDD method is the risk of hitting existing buried utilities during the pilotboring operation, which could potentiallly result in significant economic losses, disruption of services and injuries and/or loss of life. The Differential Impedance Obstacle Detection (DIOD) is a “l(fā)ook-ahead” sensory system, developed for the purpose of detecting metallic and thermo plastic pipes in the path of the boring head. The DIOD sensor was numerically simulated, and the model was validated by comparing its predictions with experimental measurements performed on a physical prototype in a controlled environment. Following validation of the model, a parametric study was undertake n to predict the performance of the DIOD under various scenarios that could be encountered in practice. 1、 Introduction Beneath the US landscape lie a vast network of buried utilities and pipelines, stretching for nearly 10.6million miles, which include natural gas lines, power lines, water distribution and collection systems and optical-fiber communication lines 1. The need for laying new utilities to support newtechnologies (i.e., the lastmile program), coupled with increasing dem ands of an ever growing population, has resulted in a highly congested underground space, particularly in urban areas. A parallel trend is the increase in the utilization of newer construction methods that minimize excavation, and reduce disruption to traffic patterns and the built environment. Horizontal Directional Drilling (HDD), a trenchless method for installing pipelines and conduits underground, has become in recent years a midstream construction method due to its versatility, cost effectiveness and relatively small foot print 2. A major concern in employing t he HDD method is the occurrence of an inadvertent utility strike during the boring process. As the drill head advances underground, it might damage an existing utility located along its path. Such utility strikes can cause significant economic losses (i.e., service interruptions, damage to a buried utility or building foundation) as well as injuries and fatalities if a hazardous utility (i.e., flammable liquid lines, electrical conduits, natural gas lines) is hit. Thousands of inadvertent utility strikes have been reported over the past fifteen years, some with severe consequences. The Damage Information Reporting Tool (DIRT), sponsored by the Common Ground Alliance, reported 258 HDD related utility hits in 2005 alone across the country 3. A specific concern during HDD installations in urban areas is the accidental placement of a natural gas line in a way that it transects a lateral connection or a gravity sewer line. Such occurrences, commonly named cross-bores, could create a long-term risk as an attempt to remove blockade in the drain (induced by the presence of the transecting gas line) could compromise the gas line, resulting in leakage of natural gas into adjacent homes via the sewer system4. Fig. 1 shows photographs of typical cross-bores created during HDD installations. Between 1996 and 200 6 at least 20 explosions occurred in 13 states due to attempts to clear sewer laterals that were blocked by a natural gasline, resulting in loss of life, severe injuries and over one hundred million dollars in damages. In one case (Madill, Oklahoma), the explosion (November 14, 2007) occurred 15 years following the installation of the natural gas line (1992). Projects undertaken by various utilities for identifying legacy cross bores resulted in the detection of an average of 2 to 3 cross bores of natural gas lines into sewer mains and laterals per each mile of sewermain inspected, which translate into several hundred cross-bores for some cities 5. Current practices for avoiding physical damage during HDD operations include search of GIS based databases (i.e., One Call system in U.S) to identify existing buried utilities within the project boundaries and surface surveys using geophysical tools such as cable locators, ground penetrating radar (GPR) and other locating methods. However, in some cases the One Cal l system is not fully effective due to inaccurate (or non-existing) records, cluttered environment (e.g., utilities that are stacked vertically or that are braided horizontally), excessive environ mental noise (e.g., overhead power lines, reinforced concrete pavement) and/or loopholes in local legislations that exempt owners of non-pressurized pipeline networks from the need to locate their assets in advance of construction projects .In recent years there were multiple efforts to develop a look-ahead sensor technology that can be incorporated within the HDD drill head in an effort to eliminate HDD related utility hits. Fig. 1. Utility hits (cross-bore) resulting from HDD installations A literature review of current and emerging look-ahead technology development efforts is presented. Thereafter, a description of the Differential Impedance Obstacle Detection DIOD system developed by the Gas Technology Institute (GTI) in collaboration with the Trenchless Technology Center (TTC) is provided. The DIOD system induces a low frequency electric fie ld within the soil medium surrounding the drill head. The obstacle is detected by measuring changes in impedance occurring due to distortion of the electric field caused by the presence of the obstacle 7. This paper describes the development and validation of a comprehensive 3-D numerical model created to predict and optimize the performance of the DIOD system. Following experimental validation of the numerical model, an extensive parametric study was undertaken to study the performance of the DIOD under varying conditions expected to be en countered in practice, including various soil types, different orientations of the obstacle with respect to the advancing drill head and different pipe (or obstacle) materials. 2、 Current and emerging borehole technologies for obstacle detection To avoid a utility strike, HDD operators have to detect buried utilities before a physical contact between the drill head and the utility takes place. In recent years several efforts have been made to develop sensor technology that could be incorporated into the HDD drill head with the capablity of detecting both, metallic and nonmetallic obstacles in near real-time. Nakauchiet al. 8 developed a small ground-penetrating radar system that is incorporated within a HDD drill head. It consists of a pair of antennas located at the cutting edge of th e drill head and protected by a ceramic cover, a signal generator, a receiver and a communication link for transfering data gathered to the ground surface. The principle of operation behind this technology is similar to that of a pulsed GPR, where an electromagnetic signal with duration of 0.6 ns is transmitted ahead of the drill head and the backscattered electromagnetic wave is used to discriminate the obstacle 8. Another GPR based technology for HDD was reported by Hirsch 9. This particular radar employed electromagnetic signals with frequencies between 25 MHz and 500 MHz. Hirsh reported that a proof of concept for the sensor was tested by pulling the prototype device through a 100 mm diamet erpolyethelene conduit, simulating the borehole created by a HDD rig, while attempting to locate metallic and non-metallic pipes located adjucent and perpendicular to the polyethelene conduit from a distance of 1 to 2 m ahead. California Energy Commission (CEC) 10 reported the development of a multisensory platform named SafeNav for HDD operations. The SafeNav system has been coupled with the AccuNav guidance system, used for establishing the location of the drill head 11. Safe Nav and AccuNavwork in conjunction to detect underground obstacles, and also to communic ate the information gathered by the various sensory systems to the surface 12. The system consists of 25 sensors including two sets of magnetometers for detecting buried electrical power lines, two sets of triaxial sensors for tracing specific frequencies for the purpose of detecting telecommunication lines, geophones for detecting acoustic signals, accelerometers for tracking the drill heads position, and temperature sensors for monitoring the operating condition of the electronics in the harsh operating conditions often associated with HDD operations. The sensors were designed to locate obstacles situated either parallel or perpendicular to the trajectory of the drill ahead. The design is compatible with most conventional directional drilling rigs. Various field tests were conducted resulting in several design enhancements 12. SoniPulse Inc. has developed a seismic based obstacle detection system for HDD. It employs an array of geophones located on the ground surface above the HDD path for detecting the seismic signals generated by the drill head 13. The seismic energy generated by the drill head is scattered by the buried obstacles along its path, and this scattered energy is recorded by geophones located 0.3 m apart. The geophones were coupled with the ground such that the signal-to background noise ratio was minimized. The high-intensity sound was continuously monitored, cross-correlated, and processed to detect peaks in the intensity. As the sound wave s generated by the drill head are too weak to detect below a certain depth, a noisemaker consisting of a rotating hammer that generates specific sound frequency was added to the drill head assembly. The technology has been tested for detecting large-diameter pipes at distances of 5 to 10 m and small diameter pipes at distances of 2 m ahead of the drill head. Fig. 2. A HDD drill mounted with DIOD； original device (top) and the corresponding CAD model (bottom). 3、 Differential impedance obstacle detection (DIOD) sensor The operating principle of the DIOD sensor is based on the Wheat stone bridge circuit. When the sensor is buried within a homogeneous soil with no obstacles (e.g., metallic pipe) in its vicinity, the bridge circuit is in a balanced state with the differential output between the sensing electrodes returning a null value. As the sensor approaches the obstacle, the impedance of the soil medium changes, and as a result the bridge reaches an unbalanced state with differential voltage observed between each pair of diametrically placed sensing electrodes. Fig. 2 show an image of a prototype DIOD sensor integrated within a mock HDD drill head as well as a 3-D CAD rendering of the sensory system. The prototype drill head is 900 mm long and 63 mm in diameter. The cutting edge (blade) of the drill head is used to inject a low frequency (50500 kHz) signal into the formation. There are four electrically isolated sensing copper electro des placed orthogonally around the circumference of the drill head ,which are in resistive cont act with the ground. In an earlier version of the sensor, the copper electrodes were capacitively coupled with the soil (copper electrodes were covered with an external plastic tube and were not in direct contact with the soil). In later versions the copper electrodes were redesigned to have a resistive coupling with the soil (direct contact with the soil) to improve contact potential 14. A practical implication of this modification is that the width of the slanted face duck-bill will need to be approximately equal diameter of the drill rod. A potential difference is maintained between the blade and the sleeve, such that the electric field originating from the blade intersects the sleeve. The differential voltage between the diametrically placed copper electrodes is measured after amplification and filtering. In a homogeneous soil medium, the output signal from the electrodes will remain steady as the drilling rod advances forward .However, when an obstacle is presents the output signal changes indicating its presence. Compared with expensive and complex high frequency electronics used in GPRs, which generally operate at from few hundred megahertz to about 2.5 GHz, the low frequency electronics (50500 kHz) used in the DIOD sensor is significantly lower in cost and complexity. This cost-effective technology concept has the potential for detecting metallic and nonmetallic objects in the soil medium, as well as identifying the position of the buried obstacle with respect to the drill head. A limitation of the DIOD sensor when compared with ground penetrating radar technology is that GPR has better spatial resolution due to shorter signal wavelength. Also, with DIOD sensor it is difficult to directly estimate the distance to the detected obstacle, whereas in a GPR the time-of-flight principle is used to calculate the separation distance from the sensor to the obstacle. 4、 Finite element modeling Numerical modeling of the DIOD sensor was carried out using the commercially available finite element software COMSOL Multiphysics with AC/DC module 15. Since the wavelengths of the electric signal used in DIOD are very large compared with the dimensions of the modeled structure, the problem was treated as static/quasi-static in nature 15. Two separate numerical models were created using the electrostatic and quasi-static modes available in CO MSOL AC/DC module. The electrostatic mode was used to predict the performance of the sensor while the drill head was suspended in open space (i.e., surrounded by air； =1), while the quasi-static mode was used to predict the performance of the sensor within a partially conductive dielectric medium (i.e., the soil formation). During simulations using the quasi-static mod e, two separate cases were considered. In the first case, approximations were made by neglecting the coupling between the magnetic and electric fields using the quasi-static electric current mode. In the second case, the coupling between the electric and magnetic fields was considered using the quasi-static electromagnetic mode。 Fig. 3. 3-D mesh of the numerical model containing a HDD drill mounted with DIOD. A 3-D rendering of the numerical model (approximately 220,000 interior elements and 19,500 exterior elements) is shown in Fig. 3. The cutting edge of the drill was assigned a value of +30 V and the sleeve was assigned a value of 30 V, similar to the actual system. The external boundary of the modeled domain was assumed to be grounded as it was sufficiently distanced from the modeled device. The interfaces between the dielectric mediums were assigned electrical continuity boundary condition. To electrically isolate each electrode from directly influencing every other electrode, a grounded metallic cylinder was placed within the Teflon cylinder. In simulations conducted using the electrostatic mode, the four electrodes we re assigned a floating potential boundary condition. In simulation runs where the quasi-static electromagnetic mode was deployed, the exterior boundaries were assumed to be magnetically insulated and the electrodes were assigned impedance boundary conditions, a condition commonly used for modeling conductive films 16. The geometry of the borehole was modeled based on the assumption that the soil was in contact with the drill head. 附錄：翻譯 水平定向鉆機障礙檢測傳感器運行建模 A.P. Jaganathan a, J.N. Shah a, E.N. Allouche a, M. Kieba b, C.J. Ziolkowski 關(guān)鍵詞： 預(yù)見性；數(shù)值模擬；差分阻抗；障礙物 探測；水平定向鉆機 摘要： 水平定向鉆進 (HDD)是一種常用的安裝地下管道的施工方法 ,管道和電纜在城市地區(qū)和跨越障礙 ,如河流、鐵路和高速公路。使用 HDD 方法的一個關(guān)鍵問題是鉆孔過程中有破壞現(xiàn)有的公用設(shè)施造成生命威脅。差分阻抗的障礙檢測 (二極管 )是一種“預(yù)見性”傳感系統(tǒng) ,開發(fā)的目的是檢測金屬和熱塑性塑料管道在鏜頭的路徑。采用二極管傳感器數(shù)值模擬 ,并通過比較其預(yù)測模型進行驗證與實驗測量物理原型在受控的環(huán)境中執(zhí)行。驗證后的模型中 ,參數(shù)研究能對二極管在實踐中可能遇到的各種情況進行預(yù)測。 1. 引言 美國景觀下埋著龐大的網(wǎng)絡(luò) 工具和管道，綿延近 10.6 百萬英里，其中包括天然氣線，電源線，配水和收集系統(tǒng)和光纖通信線路。需要鋪設(shè)新的管道，以支持新技術(shù) （即“ 用戶距離 ”計劃） ，再加上不斷增長的人口的不斷增長的需求，導(dǎo)致了高度擁擠的地下空間，特別是在城市地區(qū)。新的施工方法能最大限度地減少開挖，減少對交通的影響和建筑環(huán)境的利用率。水平定向鉆進（ HDD） ，一個非開挖方法安裝管道和地下管道的技術(shù)，已成為近年來流行的施工方法，由于它的多功能性，成本效益和相對較小的施工破壞。使用 HDD 方法的主要問題是在枯燥的過程中錯誤操作造成危險的發(fā)生。 它可能會破壞位于沿其軌道上的現(xiàn)有工具。這種操作錯誤可能會導(dǎo)致極大的經(jīng)濟損失（即損壞地下管道或建筑物導(dǎo)致服務(wù)中斷），以及受傷和死亡，過去十五年來已經(jīng)報道過上千起由于操作失誤導(dǎo)致危險管道被破壞引起事故的案例，造成了一些嚴重的后果。應(yīng)用于 HDD 的損傷信息報告工具（ DIRT ），由通用地面聯(lián)盟發(fā)起，僅 2005 年就在全國推廣。由于天然氣管線或者下水道橫切橫向連接的布置形式，在城市地區(qū)特別關(guān)注損傷信息報告，。這種情況的發(fā)生，通常稱為“交叉孔”，這種布置形式在施工過程中可能導(dǎo)致天然氣泄漏通過下水道系統(tǒng)進入相鄰的家庭。圖 1 示出的 HDD 中安裝的典型的跨孔案例。 1996 至 2006 年在 13 個州至少有 20 起爆炸事故發(fā)生于試圖清除廢棄的天然氣管線的過程中，造成了生命損失，嚴重傷害下水管管道和超過上億美元的損失。在一個案例中（馬迪爾，俄克拉何馬州） ，繼西氣東輸一線（ 1992）安裝的 15 年發(fā)生爆炸。運用各種實用程序檢測管線項目導(dǎo)致的遺留跨孔，污水干管及支管每公里監(jiān)測到天然氣線 2 3個橫孔，部分城市有幾百個交叉孔。 為避免 HDD 造成物理損壞目前的做法包括搜索基礎(chǔ)地理信息系統(tǒng)數(shù)據(jù)庫（即，在美國一個電話系統(tǒng)）利用地球物理工具，如電纜定位儀， 探地雷達，以確定項目邊界和表面調(diào)查，在現(xiàn)有的地下公用設(shè)施（ GPR）和其他定位方法。然而，在某些情況下，一個電話系統(tǒng)由于不準確的（或不存在）的記錄，雜亂的環(huán)境（例如，被垂直堆疊，或在水平方向上編織的實用程序），過度的環(huán)境噪聲（例如，架空電力線完全有效，鋼筋混凝土路面）和 /或在當?shù)氐牧⒎┒?，非加壓管網(wǎng)從需要免除業(yè)主找到他們的資產(chǎn)提前建設(shè)項目。近年來做了很多嘗試，開發(fā)出“預(yù)讀”傳感器技術(shù)，可以在硬盤驅(qū)動器鉆頭內(nèi)運行，以努力消除 HDD 造成破壞。 圖 1. HDD 中的典型案例 當前新興的預(yù)測技術(shù)是在研發(fā)文獻回顧中 提出的。此后，差分阻抗障礙物天然氣技術(shù)研究所（ GTI）與非開挖技術(shù)中心（ TTC ）合作開發(fā)檢測（ DIOD ）系統(tǒng)的描述提供。該 DIOD 系統(tǒng)引起周圍鉆頭土壤介質(zhì)中低頻電場。所述障礙物是通過測量發(fā)生由于電場引起的障礙物的存在的失真變化，阻抗檢測 7。本文介紹了創(chuàng)建預(yù)測和優(yōu)化 DIOD 系統(tǒng)的性能進行全面的三維數(shù)字模型的開發(fā)和驗證。以下數(shù)值模型的實驗驗證，一個廣泛的參數(shù)研究的目的在于研究預(yù)計在實踐中遇到的各種條件，包括各種土壤類型，障礙物的不同方向就前進的鉆頭，并根據(jù)不同的 DIOD 的表現(xiàn)管（或 障礙 ）的材料。 2. 當前和新興的鉆孔障礙檢測技術(shù) 為了避免公用事業(yè)遭到破壞， HDD 在鉆頭和工具接觸地下公用設(shè)施之前先檢測。近年來已經(jīng)開發(fā)出了一些傳感器技術(shù)，可以納入 HDD 鉆機動力頭中以檢測金屬和非金屬障礙的能力。 Nakauchi et al. 開發(fā)的是在一個 HDD 鉆頭中的小探地雷達系統(tǒng)。它由一對設(shè)在鉆頭的切削刃和陶瓷蓋組成，一個信號發(fā)生器，一個接收機和一個通信鏈路聚集到地面?zhèn)鬏敂?shù)據(jù)的保護天線。該技術(shù)的原理是類似脈沖 GPR 的，其中的電磁信號以 0.6 納秒的持續(xù)時間發(fā)送領(lǐng)先于鉆頭和背散射電磁波被用于區(qū)分所述障礙物 8。 另一種基于探地雷達技術(shù)， HDD 報告了赫希 9。這種特殊的雷達采用電磁波信號， 25 MHz 和 500 MHz 的頻率。赫希報道，證明了該傳感器是通過一個直徑 100 毫米的聚乙烯管道拉動原型設(shè)備進行測試。 加州能源委員會（ CEC） 10報道了一個名為安全導(dǎo)航 HDD 運作的多感官平臺的發(fā)展。安全導(dǎo)航系統(tǒng)已被加上準確導(dǎo)航引導(dǎo)系統(tǒng)，用于確定所述鉆頭 11的位置。安全導(dǎo)航，準確導(dǎo)航協(xié)同工作，以探測地下障礙物，并且還要通過各種傳感