Quantitative Assessment of Horizontal Directional Drilling Project Risk Using Fuzzy Fault Tree Analysis

A new method for fuzzy fault tree analysis

There are many available techniques which are widely used for failure probability analysis. Fault tree analysis (FTA) is a well-known method to identify the basic events (BEs) to reach top event. However, the FTA method in real circumstances is limited because of the many unknown and the vagueness of the situations. Thus, fuzzy set theory with respect to subjective expert opinion is employed to cope with the uncertain knowledge of BEs including randomness, ignorance, and shortages of data. In addition, to gain this purpose, much subjectivity may appear; as an example, the main one is the expert weighting. This study highlights the utility of fuzzy set theory and analytic hierarchy process to failure probability analysis in a case study. A chemical process plant has been selected to illustrate the application of proposed model with a comparison of the results with conventional model.

Human and organizational factors (HOFs) play an important role in electric misoperation accidents (EMAs), but research into the reliability of human factors is still in its infancy in the field of EMAs, and further investment in research is urgently required. To analyze the HOFs in EMAs, a hybrid method including the Human Factors Analysis and Classification System (HFACS) and fuzzy fault tree analysis (FFTA) was applied to EMAs for the first time in the paper. HFACS is used to identify and classify the HOFs with 135 accidents, reorganized as basic events (BEs), intermediate events (IEs), and top event (TE), and develop the architecture of fault tree (FT). Fuzzy aggregation is employed to address experts’ expressions and obtain the failure probabilities of the BEs and the minimal cut sets (MCSs) of the FT. The approach generates BEs failure probabilities without reliance on quantitative historical failure statistics of EMAs via qualitative records processing. The FFTA–HFACS model is applied for quantitative analysis of the probability of failure of electrical mishaps and the interaction between accident risk factors. It can assist professionals in deciding whether and where to take preventive or corrective actions and assist in knowledgeable decision-making around the electric operation and maintenance process. Finally, applying this hybrid method to EMAs, the results show that the probability of an EMAs is 1.0410 × 10−2, which is a risk level that is likely to occur and must be controlled. Two of the most important risk factors are habitual violations and supervisory violation; a combination of risk factors of inadequate work preparation and paralysis, and irresponsibility on the part of employees are also frequent errors.

Fuzzy fault tree analysis for coal burst occurrence probability in underground coal mining

Design and feasibility analysis of a fluidic jet oscillator with application to horizontal directional well drilling

Uncertainty in fault tree analysis: A fuzzy approach

Fuzzy probability on reliability study of nuclear power plant probabilistic safety assessment: A review

The serious consequences of wildfire urges scholars to pay more attention to control the occurrence of wildfire. Wildfire occurring is considered to be the result of satisfying comprehensive conditions including sufficient forest fuel, high forest fire-danger weather ratings and ignition source in this paper. In order to further study the causes and potential risks of wildfires. An assessment algorithm used for wildfires occurring risk is proposed by combining trapezoidal fuzzy theory and FTA. Furthermore, Xiangxi was chosen as application example, and the result shows that the top five dangerous BEs are ‘High average temperatures (X1)’, ‘illegal sacrifices (burning) (X23)’, ‘large underground humics (X7)’, ‘large weeds and dwarf shrubs (X11)’, ‘luxuriant tree branches (X14)’ exist highly risk. Finally, based on the evaluation results, suggestions are provided for the above basic events with greater risks.

Currently, the constant growth in the volume of the horizontal directional drilling procedure dictates the improvement of the drilling technology and the technical requirements. One of the important technical requirements for the horizontal directional drilling device is the transmission of information about drilling parameters to the operator (depth, rotation angle, inclination angle). The solution to this problem is possible with the help of measuring systems installed inside the drilling head. Traditionally, in real drilling conditions, three communication channels are distinguished: electrically conductive, hydraulic and electromagnetic, each of which has some advantages and disadvantages. The use of acoustic waves excited in the internal space of the drilling head and propagating in the material of the drilling column to the receiver allows to eliminate the disadvantages of the listed communication channels and ensure the highest quality horizontal directional drilling procedure. The paper investigates the acoustic method of information transmission in a horizontal directional drilling device. An acoustic system for positioning a drilling tool has been developed, which provides the transmission of information about the coordinates of the drilling head. The acoustic channel of information transmission has been studied in terms of constructing its structural components: the design of the probe-transmitter (electromechanical transducer) has been developed, as well as the hardware of the system. In order to determine the requirements for the modulator-demodulator of signals of an acoustic information transmission channel, the propagation of an information package was simulated taking into account the resonant properties of the converter using the Multisim circuit simulation program. Thus, the use of an acoustic system for monitoring and transmitting information about the positioning of the drilling head makes it possible to abandon expensive contact methods for determining the position of the drilling head, which give point information and require a lot of time. The proposed acoustic information transmission channel allows for tight acoustic contact between the protective container and the drilling column to eliminate power losses, increases the efficiency of the device and reduces the loss of a useful signal during its propagation and also simplifies the operation of the device. As a result, the developed acoustic system provides an opportunity to perform the highest-quality horizontal directional drilling procedure with the necessary requirements for the volume of transmitted information and stability of operation in complex noise-signal conditions, which eliminates the disadvantages of previously used methods.

Horizontal directional drilling (HDD) was used to complete two very difficult portions of pipeline construction and installation for the Port of Portland (Port) Portland International Airport (PDX) Deicing Collection and Treatment System Enhancement Project in Portland, Oregon. The PDX Deicing Project added surface runoff treatment to the existing deicing system at the Portland Airport. The project consisted of more than 8 miles of piping on Port-governed property. HDD was selected for two of the most difficult areas of pipeline construction which included a new outfall into the Columbia River and a significant active airfield crossing. The Columbia River outfall HDD installation presented several unique challenges. The installation included 1,100 feet of 30 inch polyethylene pipe. The HDD rig and boring operation was land-based while the pipe was installed using water-based floatation and insertion. Other challenges included tight in-water environmental constraints on construction techniques, activity on protected water with endangered species, crossing of an Army Corps of Engineers levee, and the need for underwater construction. The active airfield HDD installation crossed active runways, taxiways, and ramp areas, and presented several unique challenges. The installation included a 24 inch and 6 inch fusible polyvinylchloride pipe dual insertion, installed in a single 3,800 foot bore. This installation also had tight environmental challenges regarding fusion and layout areas, a significant depth of bore required under working runway and taxiway crossings, and consideration of Transportation Security Administration airfield security requirements. This paper will detail the design and construction efforts associated with both of these HDD installations and the lessons learned from both of these very challenging yet different uses of HDD methodology.

Directional boring commonly known as Horizontal Directional Drilling (HDD) is a technique widely employed in landfall areas. HDD provides advantages of crossing considerable lengths with local soil disturbance and low environmental impact, which has contributed to turn it into one of the preferred techniques between various authorities. In despite of these advantages, the corrosion protection of the HDD is complex due to the unfeasibility of installation of sacrificial anodes distributed uniformly along the HDD, which would require a remote protection engineering solution as an alternative. The remote solution adopted, the level of coating damage on the pipeline after the installation, the corrosiveness and resistivity of the surrounding environment, in particular when very different environments encounter, i.e. sea-sand-rock, are major uncertainties that must be considered on the design. In addition, the lack of recommendation on international standards and the difficulties involved with the direct inspection of the pipeline section inside the HDD increases the robustness required for the design and its verification. This paper presents the corrosion protection system of a gas line section inside a HDD in a landfall area, describing the combination of pipeline coating and cathodic protection systems both specified to resist the service life of the pipeline. After a brief review of published works related to this subject, this paper will focus on the coating and cathodic protection design presenting not only the premises, design data and methodology adopted, but also associated results and installation issues. Computing modeling and recommended practices are used to identify the best and the most feasible solution. Finally, conclusions and recommendations will be presented in order to support future projects with similar challenges.

Recently, a new fuzzy fault tree analysis (FFTA) has been developed to propagate and quantify the epistemic uncertainties occurring in qualitative data such as expert opinions or judgments. It is well known that the weakest triangular norm (Tw) based fuzzy arithmetic operations preserve the shape of the fuzzy numbers, provide more exact fuzzy results and effectively reduce uncertainty range. The objective of this paper is to develop a novel Tw-based fuzzy importance measure to identify the critical basic events in FFTA. The proposed approach has been demonstrated by applying it to a case study to identify the critical components of the Group 1 of the U.S. Combustion Engineering Reactor Protection System (CERPS). The obtained results are then compared to the results computed by the existing well-known importance measures of conventional as well as FFTA. The computed results confirm that the proposed Tw -based importance measure is feasible to identify the critical basic events in FFTA in more exact way.

The City of Fort Worth will complete the construction in April 2011 on a 12-mile reclaimed water pipeline extending from the Village Creek Water Reclamation Center (VCWRC) in Fort Worth to the south end of the Dallas/Fort Worth (D/FW) International Airport. The pipeline alignment was determined based on the close proximity to the initial wholesale customers including the Cities of Arlington, Euless, and Dallas/Fort Worth International Airport as well as future expansion. This resulted in the majority of the pipeline being designed within existing right-of-ways creating numerous conflicts that had to be resolved within the limited working room allowed. To overcome these challenges three 30-inch diameter horizontal directional drills (HDD) were designed, one of which being the longest large diameter ductile iron pipe HDD in the state of Texas. The first horizontal directional drill was approximately 1,005 LF of 30-inch ductile iron pipe to allow the pipeline to cross the West Fork of the Trinity River. The location of the crossing located adjacent to the VCWRC is on land owned by the City which allowed for adequate room to construct and string the pipeline but also resulted in high operating and surge pressures especially considering the depth necessary to cross the river. The second horizontal directional drill was approximately 955 LF of 20-inch PVC carrier pipe inside 30-inch steel casing pipe to cross State Highway (S.H.) 360. The pipeline alignment was shifted north outside of F.A.A. Boulevard right-of-way to prevent the road from being closed during construction requiring permanent and temporary construction easements on both sides of the freeway. F.A.A. Boulevard has not been constructed on the east side of S.H. 360 but the right-of-way has been dedicated allowing this area to be used for stringing the pipeline and staging for the drill. The design of this drill was challenging due to the deep and narrow highway depression, the minimal construction area on private property, and varying geologic soil conditions located within the Woodbine Formation including the possibility of large crystalline boulders. The third horizontal directional drill was approximately 1,015 LF of 20-inch PVC carrier pipe inside 30-inch steel casing pipe to cross S.H. 183. The pipeline alignment parallels an existing natural gas transmission main leading to a gas well pad site at D/FW International Airport. This resulted in limited construction space between the gas pad site and Texas Department of Transportation (TxDOT) right-of-way which required a temporary easement on private property during drilling in order to string the pipeline. The predominant challenge for this drill was due to the deep and wide highway right-of-way created by the on and off ramps at the intersection of S.H. 360 and S.H. 183.

In the past two decades, the Hillsborough County Water Resource Service Department (HCWRS) has been actively expanding its reclaimed water system in the south-central service area, both as an effluent disposal method and as a potable water saving mechanism. Currently the HCWRS reclaimed water customer base is comprised of golf course users, industrial users, commercial and residential customers. To meet increasing demands in the south-central service area and pressure requirements during the peak hours, HCWRS has identified the need for additional Reclaimed Water Transmission Main (RWTM) capacity along Lithia Pinecrest Road and Bloomingdale Avenue. To serve high demands of the fast growing communities in Hillsborough County, Florida, HCWRS is challenged with designing new transmission mains within highly congested and restricted right-of-way. For each project the Water Department designers must be conscious of the impact of surface disruption and the associated socio-economic costs to the general public, as well as the projects' overall cost. The design for the 24 in. (610mm) transmission main in Lithia-Pinecrest Road, a two-lane thoroughfare, was no different. This project was complicated by the volume of traffic in combination with portions of the alignment transitioning through a very congested right of way. The line begins at the intersection of Lithia Pinecrest Road and Bloomingdale Avenue, an east-west arterial highway and proceeds in a southeasterly direction for approximately 12,500 ft. (3.6 km) on an alignment that takes it past schools, businesses, and residential areas, and terminates at the entrance to River Hills Country Club. After a thorough analysis of the route studies and cost of open-cut construction versus horizontal directional drilling (HDD) methods, HCWRS project management chose to install the line using both open-cut and HDD construction methods. The 6,000 ft. (1.8 km) of water line installed by HDD construction would be a series of seven separate pulls using 24 in. (610 mm) flexible restrained joint ductile iron pipe manufactured by American Ductile Iron Pipe in 20 ft. (6.1 m) joint lengths. This paper will discuss in detail the comparison of the costs of the different routes and the two (2) methods of construction. It will then detail that portion of the line installed using HDD technology and address the flexible restrained joint ductile iron pipe and how using the cartridge method minimized disruption to the general public.

Portable X-ray fluorescence (pXRF) spectrometer allows fast in-situ elemental determination without wet digestion for soils or geological materials, but the use of XRF on wet materials is not well documented. Our objective was to develop a rapid field method using pXRF to measure metals in the residues from horizontal directional drilling (HDD) operations so that proper disposal decisions can be made in-situ. To establish the procedure, we spiked soil samples with 4 concentrations of Cr, Ni, Cu, Zn, As, Cd, and Pb up to 1000 mg kg−1, and then the metal concentrations were determined by wet chemical method after drying and acid digestion (standard method), and by pXRF, also at laboratory conditions, after drying and at two different moisture conditions. The measurements by pXRF and standard method after drying and after removal of excess water (AREW) were highly correlated with slopes ranging from 0.83 ± 0.01 to 1.08 ± 0.01 (P < 0.001) for all metals. The relationship was better AREW than the saturated paste without removal of excess water and the moisture content affected only the accuracy of As, Cd, and Pb. The procedure established was successfully used for HDD residues collected from 26 states of US with moisture content ranging from 14 to 83% AREW. The pXRF was proven to be a reliable tool for fast detection of common metals in dried soils and HDD residues, and samples containing < 30% moisture content without needing to correct for moisture. If the moisture is > 30%, excess water in samples need to be removed with a commercially available filter press to achieve high accuracy. The developed procedures reduce time of metal detection from days to about an hour which allows drilling operators to make quick decisions on soil or HDD disposal.