Journal of Pipeline Systems Engineering and Practice

The required pulling loads on pipes installed by horizontal directional drilling (HDD) are related to the route characteristics and various implementation parameters, some of which are directly controllable. The application of ASTM Standard F1962, Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit under Obstacles, Including River Crossings, has been conveniently employed to perform a parametric study to help understand the dependency of the pull loads on these variables and the corresponding installation characteristics. The results provide useful information to help focus on the more significant parameters that affect the pull loads, thereby helping to ensure successful installations. Some of the results are as expected, including the effectiveness of antibuoyancy techniques for dramatically reducing the required pull loads; other trends are less obvious. While the ASTM F1962 methodology is intended to be applicable for the placement of polyethylene pipe, the conclusions and guidelines may reasonably be extrapolated to other types of pipe.

High-density polyethylene (HDPE) pipelines are commonly installed using horizontal directional drilling (HDD), a trenchless construction technique used to replace or expand underground pipelines which generates cyclic axial forces on the pipe. To evaluate the ability of existing linear and nonlinear viscoelastic models to predict HDPE pipe response during this cyclic loading, calculations of axial strain are compared with the laboratory measurements. The linear viscoelastic and nonlinear viscoelastic models provide reasonable estimates of the maximum strain levels during installation; however, maximum strains were underestimated by the linear viscoelastic model and overestimated by the nonlinear viscoelastic model. During periods of strain reversal, both models overestimated the amount of axial strain recovery. A parametric study showed how the magnitude of these strains depends on the peak stress during each cycle, the number of cycles, and the period of time stresses are applied. The work also quantifies how increases in peak stress and the number of cycles increase the maximum axial strain. Conventional creep functions can provide reasonable conservative estimations of the maximum strain during a HDD installation provided that the maximum pulling force is known.

In order to advance the state-of-the-art in pneumatic capsule pipeline (PCP) underground freight transportation science, this paper examines the problem of separating capsules that may naturally form into trains as they travel through the pipeline. Such separation of capsules is necessary when the capsule trains approach branching points in the system. The analysis is performed for the simplified case of a train consisting of two capsules in a typical $1.0{\text{-m}}^2$ cross section PCP. The capsules enter and traverse a multisegmented linear induction motor (MSLIM) that is to be used to separate them prior to reaching the branching point. Separation distances and times have to be large enough to allow a switching operation to be performed on the first capsule before the second capsule arrives at the switching point. Results of the analysis show how the first capsule will accelerate and how the second capsule will decelerate, thus causing separation. The results also show that reasonable capsule-separation distances and times can be achieved in reasonable amounts of time with reasonable lengths of MSLIM.

Horizontal directional drilling (HDD) has become increasingly used for the construction of large diameter (more than 600 mm or 24 in.) pipeline projects throughout China. Due to the large investment of capital and resources, it is important to conduct a risk evaluation prior to actual construction. However, there are relatively few appropriate analyses or investigations available for such applications. This paper addresses the risk assessment for Maxi HDD projects. The combination of the fuzzy comprehensive evaluation method and analytical hierarchy process was adopted as the basic model. The corresponding risk indices were constructed considering the factors affecting the projects and based on discussions with experts who have conducted HDD crossing projects. Structured judgment matrices and membership matrices were then directly developed from the index systems, and the weight vectors, subordinated vectors, and risk values determined by the use of Matlab software. Finally, the risk level of the projects was obtained by implementing the maximum membership degree law. The synthesis of the fuzzy comprehensive evaluation method and analytical hierarchy process has been demonstrated to provide a theoretical basis for the risk evaluation and establishment of risk control measures for Maxi HDD projects.

Traditional asset internal condition assessment inspection techniques gather data that improve the understanding of an asset’s condition and capacity performance. Inspection data are difficult to compile because of the differing ways the inspection data are collected and documented. This drove the need for a modified data collection and analysis process. An integrated asset scoring and multiple inspection scoring process was developed after reviewing and assessing the availability of existing industry approaches. A unique method of applying a common scoring scale of 1–100 to each inspection technique was developed using a combination of advanced root-square-mean mathematical principles. The benefits of the integrated inspection process are that large amounts of field inspection data can be screened, analyzed, and consistently prioritized using automated processes saving considerable labor resources and expediting corrective action solutions. These features will aide utility owner efforts to efficiently and effectively address both asset management and capacity driven projects.