Horizontal Directional Drilling Research Articles

Evaluating tidal impact on ground source heat exchanger performance under fluctuating groundwater levels

Coastal regions undergo dynamic changes due to tidal forces, posing distinct challenges for groundwater management and utilization of ground source heat pump (GSHP) systems. This study examines the impact of tidal fluctuations on groundwater levels and the performance of ground heat exchangers (GHEs), specifically focusing on the suitability of horizontal directional drilling (HDD) technology in high-tidal zones. Itoman City in Okinawa Prefecture, Southern Japan, serves as an ideal location for this study due to its complex coastal hydrogeological conditions and increasing interest in renewable energy solutions. Employing a comprehensive approach involving field experiments, FEFLOW software simulations, and model validation, we aim to elucidate the intricate relationship between tidal dynamics, groundwater behavior, and GHE performance. Furthermore, our investigation assesses the effectiveness of HDD-GHEs installed in highly tidal-affected zones to determine the optimal installation depth for this type of GHE in coastal regions. According to our research, the layer at a depth of 30 m is most affected by tidal influence and fluctuations in groundwater levels in coastal regions. This layer is the most suitable for installing horizontal HDD-GHEs, with an average heat exchange rate of about 89 W/m. This rate is approximately four and two times higher than the depths above and below this layer, respectively, due to groundwater saturation and flow in the formation. Furthermore, we noticed that the heat exchange rate increases from the top to the bottom of this layer, but the extent of this increase diminishes as the depth increases. This is because deeper depths are less affected by tidal fluctuations in groundwater levels.

Challenges with using empirically determined geotechnical parameters for borehole stability evaluation in horizontal directional drilling

Geotechnical parameters required for estimating the maximum allowable annular pressure (Pmax) in horizontal directional drilling (HDD) are often empirically determined based on the results from the standard penetration test (SPT). Despite the benefits of SPT, its use in practice could be challenging as the geotechnical parameters determined based on SPT results vary largely depending on the choice made for SPT correlations. Such variability within the geotechnical parameters could result in a high degree of uncertainty within the estimates of Pmax in HDD. In this paper, an SPT-based algorithm is developed to study the variation in estimates of geotechnical parameters and Pmax due to the choice made for SPT correlation. Sensitivity analysis conducted using the SPT-based algorithm presents significant variations in both estimates of geotechnical parameters (relative ranges vary from 11% to 1516%) and Pmax (relative ranges vary from 10% to 1313%) for cases where the understanding of soil behavior and characteristics is insufficient. Error analysis conducted based on the errors in the geotechnical parameters determined using SPT correlations and the corresponding estimates of Pmax presents that the two types of errors are found closely related for most cases; however, exceptions also exist for the cases with the SPT correlations related to modulus of elasticity. Based on the results of the error analysis, suggestions for the use of SPT correlations are made for determining the input geotechnical parameters required for estimating the Pmax in HDD, and they are applied to a case study related to the hydraulic fracture experiments to demonstrate their usefulness in a real-world example. The case study presents high precision (R2 > 0.81) in the estimates of Pmax obtained by following the suggestions for the use of SPT correlations. In remark, the estimates of Pmax made based on some SPT correlations are found nearly equal to the measurements of annular pressure at hydraulic fracture, confirming that the SPT-based algorithm and the suggestions for the use of SPT correlations provided herein are reasonably reliable for estimating the Pmax in HDD. These results highlight the challenges with using empirically determined geotechnical parameters in the design of HDD and provide practitioners with valuable information for evaluating the stability of the HDD borehole.

Effect of pulsating flow induced by a percussive drilling tool on cuttings transport in horizontal directional drilling—A CFD study

Cuttings deposition and removal has always been a key issue in horizontal directional drilling due to its correlation with numerous problems such as rate of penetration, reduction and stuck pipe.In this paper, the relationship between the impulse flow generated by a fluidic jet hammer and cuttings removal was discussed. A Eulerian-Eulerian two-fluid model was used to simulate the cuttings transport in horizontal wells on a sliding grid basis. Results show that the flow pulsation induced by a fluidic hammer contributes to easier cuttings transport. Compared to constant flow, impulse flow showed a 22.03% improvement in more optimal borehole cleaning with the same system inlet flow rate. In addition, the asymmetric flow pulsation was more sensitive to amplitude than the sinusoidal waveform pulsation flow, and as amplitude increased, the average exit flow rate of cuttings increased by 30.95%. Cuttings transport in annular is sensitive to rate of penetration, average velocity of pulsation, pulsation amplitude and cuttings size. The effect of pulsation frequency seems to be not much significant, probably because the frequency or other parameters used in this work did in the range of optimal particle-carrying frequency. These findings can provide references for the utilization of downhole pulsating fluids by drilling tools.

Radar Method for Obtaining Information from a Horizontal Directional Drilling Device

Radar Method for Obtaining Information from a Horizontal Directional Drilling Device

Dynamic Response of Buried Natural Gas Pipelines under Horizontal Directional Drilling Loads

Due to the unobservable nature of underground construction and the destructive nature of horizontal directional drilling rigs with high power, this type of construction has become one of the most important causes of failure of long-distance natural gas pipelines. In recent years, horizontal directional drilling construction has caused pipeline accidents frequently. Once the accident occurs, the normal operation of natural gas pipelines cannot be ensured. Therefore, studying the damage mechanism of buried natural gas pipelines under horizontal directional drilling loads is important for the safe operation of pipelines. This paper combines the construction characteristics of horizontal directional drilling and the actual situation of natural gas pipelines to explore the relationship between horizontal directional drilling and pipelines. The force situation of pipelines after contacting directional drilling bits is analyzed by the drill bit-soil-pipe finite element model created in the ABAQUS software. The Johnson–Cook ductile damage model was utilized to determine the pipe’s damage condition. The sensitivity analysis results show that he order of the impact of key parameters on the dynamic response of the pipe is bit thrust [Formula: see text] wall thickness [Formula: see text] bit diameter [Formula: see text] pipe diameter [Formula: see text] bit speed [Formula: see text] number of bit teeth [Formula: see text] pipe operating pressure. Therefore, priority should be given to controlling the size of the drilling thrust and the speed of the drill bit to reduce the damage to pipelines by horizontal directional drilling construction. In addition, appropriately reducing the pipeline operating pressure can also reduce the risk of the pipeline being damaged by horizontal directional drilling construction.

Construction of an acoustic information transmission system of a horizontal directional drilling device

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.

Experimental study on environmental chemical effect and purification treatment of waste slurry in horizontal directional drilling

The waste slurry generated during Horizontal Directional Drilling (HDD) has detrimental effects on water sources, soil, and organisms. Existing studies lack quantitative analysis and assessment of the environmental hazards of waste slurry. The treatment of waste slurry is usually done by physical curing or chemical curing agents. The treatment effect of these treatments is unsatisfactory or not environmentally friendly enough. Research on the application of Microbially Induced Calcite Precipitation (MICP) in waste slurry purification can help provide innovative solutions. This study began by acquiring the basic properties, mineral composition, and particle size distribution of the waste slurry through experiments. The effects of different concentrations of waste slurry on soil chemical properties were compared, including the measurement of total dissolved solids (TDS), turbidity, and heavy metal ion concentrations of waste slurry supernatant. Additionally, the environmental impact of the waste slurry was assessed from an electrochemical, turbidity, and ionic composition perspectively. A combination formulation containing 2.8 wt% urease, 5 wt% urea, and 3.5 wt% calcium chloride was used to purify the waste slurry. The supernatant of the MICP treated waste slurry undergoes electrochemical testing to evaluate the effectiveness of MICP technology for slurry treatment. The findings indicate that both chemical additives and stratum contaminants significantly contribute to slurry pollution. When the waste slurry constitutes more than 40 wt% of the soil mass fraction, the electrical conductivity (EC) of the soil surpasses the threshold of 1000 μs/cm, and the pH level rises to approximately 9.5, rendering it unsuitable for plant growth. Moreover, the TDS, turbidity, and heavy metal ion concentrations in the waste slurry supernatant exceed the permissible environmental discharge limits. Notably, the concentration of arsenic (As) exceeds the national standard by 18 times, cadmium (Cd) by 20 times, and selenium (Se) by 208 times, posing a high risk of environmental pollution. However, the comparison of ion concentrations in the supernatant before and after MICP treatment reveals that MICP demonstrates effective cementation and co-precipitation of heavy metal ions. MICP purified 66.6 % of arsenic (As), all cadmium (Cd), 75 % of phosphorus (P), and 76 % of selenium (Se) from the waste slurry supernatant. The results of this research contribute to the quantitative evaluation of the environmental hazards of waste slurry. It also helps to promote the application of MICP in waste slurry purification.

Optimization of double layered horizontal directional drilled ground heat exchangers by water injection into the borehole

Ground Heat Exchangers (GHEs) drilled using Horizontal Directional Drilling (HDD) technology have been proven to be a cost-efficient way of installing ground source heat pump systems (GSHP). They can also be installed in places where conventional horizontal ground heat exchanger (HGHE) would not be possible e.g., due to lack of land.In this research, a double layered horizontal borehole was installed as a GHE in Saga City, Japan. The two holes had a diameter of 114.3 mm and a length of 59 m and 56 m, respectively, while reaching depths of 5 m and 9.5 m. A polyethylene pipe with an outer diameter of 60 mm was inserted as a borehole heat exchanger (BHE). In March 2022, a two days thermal response test (TRT) showed the influence of rainfall on the system. A numerical model developed in FEFLOW based on the GHE dimension and the region's geology was validated using the measured temperatures of the heat medium at the return point and outlet of the GHE during the TRT. The validated model was then used to carry out sensitivity analysis examining different conditions of water injection into the borehole. The result of the sensitivity analysis showed that water injection into the borehole can improve the performance of the system and reduce the temperature change of the heat medium. Varying the injection rate can improve performance to a certain degree and the injection point has a strong influence on the performance. The injection temperature was also found to play a role in the performance, but even high temperatures in the case of heating showed significant improvement. Lastly, the influence of permeability was investigated and showed that impermeable layers are more favorable for injection compared to permeable layers.

Mud infiltration and travel paths during mud loss experiments on horizontal borehole stability

Excessive mud pressure may endanger stability of horizontal boreholes and the success of drilling and reaming processes during Horizontal Directional Drilling (HDD). However, no laboratory studies have been undertaken to investigate the relationship between horizontal borehole instability (resulting in mud loss rather than borehole collapse) and mud infiltration and travel paths from the borehole to the ground surface. In this paper, exhumations after a series of mud loss experiments in a medium-scale test pit are used to explore mud infiltration into the sand surrounding the borehole, and the paths used to travel from the borehole to the ground. Different factors are investigated including burial depths, pump rates and the effect of multi-layered soil systems (dense sand covered by different thicknesses of loose sand or dense sandy gravel). Details of the mud travel paths from the experiments are presented. Water contents and average radial extent of mud infiltration around the boreholes are summarized. It is concluded that shear failure of the sand has a dominant role in defining the mud transport through coarse-grained soil. A primary crack appearing on the ground surface approximately above and parallel to the borehole, and secondary cracks transverse to the primary cracks then developed, linking the volumetric expansion of the sand due to mud intrusion and uplift at the ground surface. Ground movements are more dramatic in experiments involving high pump rate but the movements were reduced in experiments involving multi-layered soil systems.

Research on Horizontal Directional Drilling Scheme for Large Cross Section Submarine Cable Crossing Hard Rock

With the increasing number of submarine cable projects, the terrain and geological conditions of the landing section are becoming increasingly complex, and the traditional implementation of trench burial is becoming increasingly difficult. A landing construction plan for large-section power cables suitable for steep terrain and rugged rock formations is studied and proposed based on sorting out existing submarine cable landing plans. Using directional drilling construction machinery ideal for rock formations, natural cable protection pipes are formed in rock formations after dragging and expanding the holes, meeting submarine cable protection’s safety and economic requirements. In the climbing section of the submarine cable from the seabed to the rock hole, measures such as bottom sandbag raising and top rock throwing security are adopted to avoid vortex-induced vibration and erosion caused by the cable hanging in the climbing section. The construction plan of the directional drilling passage through hard rock and the construction and protection plan of the submarine cable do not affect the current situation of the existing coastal reefs and can effectively protect the submarine cable from external damage, achieving green and environmentally friendly construction.

Assessment of the technical level of installations horizontal directional drilling

The article considers the concept of the technical level (TL) of engineering products, the regulatory and technical foundations and the need to assess the TS at each stage of the machine’s life cycle. The fundamentals of horizontal directional drilling (HDD) technology work are considered. The review and classification of modern HDD installations depending on the technical parameters of the equipment is given. The results of an expert assessment of the indicators of the significance of HDD equipment parameters are presented. Calculations of specifications TL for the presented equipment were carried out. The results of the study are presented in graphical form. The article is published based on the results of the research work carried out as part of the competition for grants for the implementation of research work by scientific and pedagogical workers SPbGASU in 2023. Keywords: technical level, technique, horizontal directional drilling, efficiency, parameter

Discussion of “Accuracy of Pull Force Estimation for Steel Pipe Installations Using Horizontal Directional Drilling: Review of 200 Case Studies”

Discussion of “Accuracy of Pull Force Estimation for Steel Pipe Installations Using Horizontal Directional Drilling: Review of 200 Case Studies”

Borehole TV Imaging Technology for Horizontal Directional Drilling Based on an Optimization Algorithm for Structural Planes

The horizontal directional drilling technology combined with the borehole TV imaging technology can be used to obtain most of the geological information in conventional adit exploration. This combination has little impact on the environment and is free from topographic constraints, thus contributing to green exploration. However, conventional algorithms for structural planes fail to accurately extract information on the attitudes of incomplete structural planes in boreholes of any azimuth. Moreover, existing borehole TV devices are mostly cable-based and, thus, difficult to put in place in horizontal drilling. They are prone to get stuck in the collapse section of boreholes, thus damaging the devices. Given these challenges, this study develops an optimization algorithm for structural planes: (1) first, information on multiple points in the 2D unfolded view is fitted using a sinusoidal function curve, three arbitrary points are constructed using the fitted curve, and the normal vector of the plane determined by the three points is calculated; (2) the normal vector in the geodetic coordinate system is obtained after two rotations of the spatial coordinate system based on the theory of transformation of Cartesian coordinate system; (3) finally, the dip angle and dip direction of a structural plane are calculated using the normal vector in the geodetic coordinate system. By making the best use of the information on multiple points in the 2D unfolded view, the optimization algorithm can overcome the defect that is difficult for conventional two-point methods to locate the highest and lowest points of discontinuous structural planes. Therefore, the optimization algorithm applies to calculating the attitudes of structural planes in boreholes of any azimuth. Based on this optimization algorithm, this study successfully develops a cable-free, storage-based TV device for boreholes of any azimuth. This device was employed for laboratory experiments on 20 complete structural planes and 32 incomplete structural planes. As indicated by the experiment results, the optimization algorithm proposed in this study is applicable to many types of structural planes, with a dip direction error of less than 10° and a dip angle error of less than 5°, thus meeting the production requirements.

AN INTEGRATED GEOTECHNICAL INVESTIGATION FOR STRUCTURAL FOUNDATION SUITABILITY ACROSS NIGER RIVER, NORTH CENTRAL NIGERIA

- The need to assess the suitability of foundation soil for oil and gas installations, such as pipeline, stations, and all other ancillary facilities, necessitated this study across the Niger River of north central Nigeria. A total of 17 boreholes and cone penetration tests were conducted. Samples were recovered from the boreholes and tested in the laboratory to obtain soil parameters. The investigation revealed that the subsurface is essentially composed of FINE SAND/SAND and CLAY. The FINE SAND is largely the superficial soil except in BH1 where CLAY is the superficial soil. The FINE SAND is loose at the top becoming medium dense and clayey at the base as it grades into CLAY. It has a greyish colour, with moisture content between 6% and 29% and bulk unit weight between 15.17 kN/m3 and 21.76 kN/m3 . The CLAY underlies the FINE/SAND and SAND. It is generally greyish in colour, with moisture content between 12% and 29% and bulk unit weight between 15.17 kN/m3 and 21.30 kN/m3 and an average strength of 156 kN/m2 except where it is the surficial soil and soft (strength < 25 kN/m2 ). Oversize materials were not encountered during the investigation and as such shall not pose any risk to horizontal directional drilling operation. However, on the Island, within the FINE SAND, bed of gravel occurs in BH8 and BH9. In terms of plasticity, due to saturation, the soils are not expected to swell. Nevertheless, it is advisable to add polymers to the drilling mud to prevent transfer of water from the drilling fluid into the soil as a precaution for clayey soils at the entry and exit points and on the Island. Most of the soil contains fines less than 30% and therefore, specific measures may be employed to improve borehole stability during drilling and installation.

Experimental and numerical study of measuring in-situ stress in horizontal borehole by hydraulic fracturing method

Horizontal directional investigation is an alternative method different from traditional (vertical) geotechnical investigation, which can effectively reflect geological conditions along the axis and evaluate the engineering characteristics of tunnels in mountainous areas with super long distances and depths. However, the absence of effective methods to measure in-situ stress in horizontal boreholes hinders the promotion of horizontal directional investigation. This paper relies on the thorough horizontal directional drilling geotechnical investigation of the Tianshan Shengli tunnel in China, based on the method of hydraulic fracturing in-situ stress measurement, the relationship between the direction and magnitude of in-situ stresses and the parameters of the hydraulic fracturing was established in a horizontal borehole by enhancing the previous model of inclined boreholes. The interpretation principles of horizontal boreholes by hydraulic fracturing method are further explored through experimental and numerical study. The conclusion of this paper provides theoretical and empirical support for in-situ stress measurement in horizontal boreholes by hydraulic fracturing method.

An experimental study of Horizontal Directional Drilling (HDD) in sand in a large flexible calibration chamber

Horizontal Directional Drilling (HDD) is a trenchless technique for underground infrastructure installation that uses pressurized drilling fluid. Excessive loss of fluid to the formation can cause problems not only for the execution of HDD but also to nearby structures and must, therefore, be avoided. Hydraulic fracture is one of the possible causes and theories to predict the ultimate pressure have been developed, mostly for clays. Luger and Hergarden (1988, apud Keulen, 2001) developed a hydraulic fracture model particularly for HDD. The present study presents an experimental program carried out on a large flexible calibration chamber in sand using drilling fluid and confining pressures compatible with HDD field conditions. Results show that while local fracturing may occur, causing injection pressure to decrease for a while, permeability is still the dominating factor.

Development of annular pump to enhance drilling distance and cuttings return in horizontal directional drilling

In many shallow horizontal directional drilling (HDD) projects, the annulus fluid pressure soon reaches the blowout or frac-out pressure of the soil formation. The pressure at single-source pump therefore must be limited. This limits the maximum drilling distance (borehole length), maximum attainable rate of penetration (ROP), and maximum distance over which cuttings can be returned. A novel concept involving a series of annular pumps distributed along the borehole length to aid in generation of distributed annulus pressure boost and cuttings transport in HDD was conceived. The success of the above concept, designated as distributed pumping system (DPS), relies on the ability to design and power an annular pump that can fit in the constricted annulus geometry of HDD boreholes while satisfying the performance requirements. We present the laboratory-scale development of three annular pumps based on the turbomachinery design principle of axial blade propellers. The pump prototypes were 3D printed and tested in the laboratory test rig flow loop built to simulate the annular flow configuration of HDD boreholes. The annular pump was powered using the axial propeller turbine housed inside the hub of each annular pump. The turbine converts hydraulic energy from the inner flow (analogous to drilling fluid flow within drill rod) to power the integrated setup of the axial inner turbine and annular pump, in short, designated as integrated turbine-pump (ITP). Results from the tests on three preliminary prototypes of the annular pump using water as the medium in the test rig yielded a maximum pressure boost of 44 kPa–enough to space the annular pumps 80 m apart when designed for a typical annular pressure drop rate of 0.54 kPa/m. The performance index (i) of the ITP, defined as the ratio of pressure boost provided by the annular pump in the outer (annular) flow to the pressure drop created by an inner turbine in the inner flow, reached a maximum value of 0.6. The results from the study promise a technology that can enable long-distance HDD cuttings return without the risk of blowout or the need for an external power source.

The efficiency of the horizontal directional drilling method in the rehabilitation and modernization projects of the underground infrastructure

"The evolution of human society was and is dependent on natural resources (oil, natural gas, coal, ores, industrial water, drinking water, etc.) and, obviously, on their transportation through pipelines. The existence of resources in the earth's crust, at depths not always accessible, required the finding of methods for their exploration and exploitation. Consequently, in the last 30 years, drilling methods, techniques and technologies have been developed. Today, the Horizontal Directional Drilling method covers the entire geological spectrum, and in terms of rehabilitation and modernization projects of the underground infrastructure, it ensures high quality. Therefore, Horizontal Directional Drilling is the smart, clean and efficient solution for installing the network sections to be installed. The authors, under the auspices of the Romanian Academy of Technical Sciences (ASTR) and the General Association of Romanian Engineers (AGIR), in this paper, highlight the use and advantages of Horizontal Directional Drilling. The main objective is to install such services in Romania without using traditional trenching methods, helping to avoid any unnecessary impact on the environment and, evidently, offering extra security. "

An Introduction to Horizontal Directional Drill Installation of High-Voltage Transmission Lines and Other Duct Banks: Improving on Conventional Overhead Transmission Lines

Horizontal Directional Drill (HDD) installation of high-voltage (HV) transmission has proven practical, and in some cases, less costly than traditional overhead options. Petrochemical facilities located on waterways provide excellent opportunities for underwater HDD-installed transmission lines. These designs can provide significant safety advantages as well as improve system reliability. They eliminate the height restrictions associated with overhead lines, reduce air traffic obstructions, and reduce the weather-related concerns typically associated with traditional overhead transmission lines, especially highly elevated transmission line crossings over waterways. They also offer significant opportunities when expanding existing facilities and designing for Prevention through Design by eliminating the overhead transmission and their associated contact risks throughout the life of the installation. Each HDD-installed transmission line is different and can create significant challenges; however, the benefits associated with this technology can significantly outweigh the effort. This article reviews some of the challenges associated with long, high-capacity transmission line installations, along with their associated solutions as incorporated in previous projects. This article does not cover the smaller and shorter HDD installations typically associated with electrical distribution commonly used to cross streets, highways, or feed commercial facilities.

Numerical study on mechanical properties of pipeline installed via horizontal directional drilling under static and dynamic traffic loads

The present study investigates the mechanical behavior of pipes installed via horizontal directional drilling method, a typical trenchless method for highway-crossing pipeline installation, under traffic loads. The effects of both stationary and moving vehicles are considered in the analysis. Results from the static analysis indicate that the pipe experiences maximum stress at its top, with minimum stress at its bottom. Furthermore, the stress change in soil is more significant than that in the pipeline as the vehicle weight increases. When a moving vehicle passes over the pipeline, the stress of the pipeline remains relatively constant. No significant change in pipe stress is observed with changes in vehicle weight and speed. However, when the vehicle speed approaches 100 km/h, the maximum soil stress decreases significantly. Conversely, the pipe stress is higher when the vehicle is stationary compared to when it is moving. A comparison is made between the mechanical behavior of pipes installed via horizontal directional drilling and open-cut methods under traffic loads, with the results revealing that the stress of pipelines installed via horizontal directional drilling method is higher than those installed via open-cut method in both static and dynamic analyses. Nonetheless, the stress variation amplitude of pipelines installed via horizontal directional drilling method is smaller during vehicular passage, thus indicating a lower possibility of fatigue failure caused by traffic loads.