Pipe Jacking in Difficult Urban Waterfront Conditions

The engineer’s role in any design project is to design a project that meets the desired purpose, is constructible, and the health, safety, and welfare of the user is protected. Yet engineers do not always recognize the consequences of their designs. Civil engineering is a profession that holds life and death consequences. When engineers design a project, an error or mistake could result in property damage, personal injury, or death. Not understanding a product, while allowing its use, may equate to negligence if injury results. Not reading the product literature may also constitute negligence, should the product’s failure result in injury or damage. When products fail the engineer may be deemed the responsible party. Many engineers do not understand, or appreciate, the differences between reinforced concrete pipe (RCP) and high density polyethylene (HDPE) pipe and the potential for liability when specifying each product. Whereas RCP is a rigid structure that is designed, built, and tested as a structure before it arrives at the construction site, the “structure” of HDPE pipe is actually built and tested in the field. Hence, HDPE pipe is not an “approved equal” substitute for RCP. This paper reviews the critical aspects regarding the decision to specify corrugated HDPE pipe. Know the difference.

High density polyethylene (HDPE) pipes are being installed as buried conduits at an increasing rate. HDPE pipes are lightweight and resistant to corrosion and abrasion. Because HDPE pipes are flexible, the soil embedment is a major component of the conduit. To assure adequate pipe stiffness, corrugated and profile wall pipes are becoming available. Design is based on pipe-soil interaction using fundamental principles of pipe and soil mechanics. This paper examines performance and performance limits and suggests design procedures for typical installations.

The pipe jacking method is relatively reasonable among trenchless construction methods.For the application of this method, the acid sulfate soils have negative impacts on filling materials (one of the cement materials) injected into the tail-void which are over-cutting areas formed to reduce the friction between the pipes and the surrounding soils. In thisstudy, the application of fly ash and slag is discussed to minimize the effect of sulfur acid to filling materials. As the results of the experiments, the addition of fly ash and slag can control the gelling time and prevent the reduction of uniaxial strength of filling materialsunder the acid sulfate soils. In addition, the filling materials added slag lowered frictional resistance compared to that of fly ash. Fillingmaterials with the lower frictional resistance are preferred to apply for the smooth pipe jacking constructions. Therefore, filling materials added slag would show better performance than that of fly ash under the acid sulfate soils due to its lower frictional resistance.

This paper discusses a value engineering study, design, and construction of a sanitary sewer siphon using high density polyethylene (HDPE) pipe in San Juan, Puerto Rico. The value engineering study evaluated pipe options and construction methods and recommended the use of HDPE pipe constructed in the wet for the Rio Puerto Nuevo river crossing. The design of the pipe included development of the horizontal and vertical alignments, pipe hydraulics, selection of pipe wall thickness, and pile clearance analysis. The HDPE pipe is joined using heat fusion, launched into the river, and covered. This paper also discusses details of the construction, which is in progress.

Studies on Surrounding Soil during Construction using the Deep Pipe Jacking Method in the Deep Strata

This article presented a case study on a pipe jacking tunneling project crossing underneath the Bang Prakong River in Thailand. This project belonged to the Thailand Irrigation Department and connected between the Klong Phra Ong Chaiya Nuchit and the Bang Pakong River. The technique and process of tunnel construction crossing the river by pipe jacking method were described in details. Moreover, the technique and process of shaft construction technique for jacking pit and receiving pit by sinking method were explained. The jacking pit was collapsed so it was reversed to be the receiving pit. This pit was rebuilt by the steel casing. Then the new jacking pit was improved from the old receiving by the jet grouting method. The jacking force was controlled under 900 Ton. The horizontal deviation was in between ±60 mm and the vertical deviation was in between ±70 mm along the tunnel line.

Understanding the force characteristics of pipe jacking in rock formations is crucial for ensuring the stability of the structure and construction safety during construction. Yet, very little is explored about its characteristics in rock formations of pipe jacking. This paper presents a case study of constructing a deeply buried moderately weathered slate sewage pipeline using pipe jacking method in Changsha, China. To this end, we propose a novel method to combine field monitoring and numerical simulation representation in an efficacious way. Field monitoring was conducted to investigate the spatial distribution characteristics of jacking force, axial stress, and hoop stress in moderately weathered slate. Numerical simulation methods were employed to discuss the influences of several factors on pipe stress: the pipe-rock contact area, contact relationships at pipe joint interfaces, the height of the jacking force position, and the depth of pipe burial. The results show that hand shield is influenced by the excavation technology, and the distribution of jacking force exhibits a stepped or oscillating upward pattern in moderately weathered slate. The maximum axial stress occurs at the mid-span position of the arched roof of pipe at 30 MPa. Hoop stresses are dominated by compressive stresses with the maximum at-8 MPa. As the pipe burial depth increases, so does the axial stress on the pipe. Lower positioning of the jacking force heightens this stress effect. A larger pipe-rock contact area correlates with reduced axial stress levels. The weakening of the contact interface between pipe joints minimally affects axial stress, as stress primarily transmits through non-weakened areas. To ensure the reliability of the data, automatic monitoring and measuring instruments calibrated for on-site monitoring are used. The results of this study can provide beneficial guidance for the design and construction of pipe jacking.

Lead (Pb) deposition onto new and biofilm-laden potable water pipes

Due to a high demand of space utilisation in metropolitan area, the existing tunnels, which are normally used for underground transportation and service utilities, can be suffered from the impacts caused by the adjacent constructions. In general, the protection zone of a tunnel is developed based on the assumption of shear plane of soil, rather than the soil–structure interaction. The assessment of the impacts of new construction nearby the existing tunnel is thus essential for improving the protection zone. 3D finite-element analyses are conducted for the case of the mass rapid transit (MRT) tunnels in soft ground. The impacts on the MRT tunnels from two possible underground construction cases (i.e. open cut and pipe jacking) are investigated in terms of tunnel deformations and changes in tunnel lining moment. The advantages of using 3D analysis are to model the realistic soil–structure interactions and to observe the multidirectional impacts on MRT tunnels. The results show that the bending moments increased by both open cut and pipe jacking construction activities are relatively small. For the tunnel deformations, most cases are sufficiently secure, but only in some cases, the deformations of tunnel lining almost reach the limit of 6 mm. However, it is highly recommended that they are still required to numerically examine in case by case

High density polyethylene (HDPE) pipes were prepared using a novel rotational extrusion processing system. The experimental results showed that the hoop stress exerted by either mandrel rotation or die rotation could have the macromolecular chains oriented in hoop direction and alter the crystallization behavior of HDPE during rotational extrusion, resulting in forming transcrystals with larger crystalline size, thicker lamellae, higher Tm. Therefore, the mechanical properties of HDPE pipes were greatly improved in hoop direction, which was attributed to the changes of the crystalline morphology and the molecular orientation under the action of the hoop stress field.

NSF/ANSI Standard 14 (NSF 14) was developed in 1965 to establish a standard for the testing and certification of plastic materials for both toxicological health effects as well as performance. At the time of introduction, NSF 14 covered pipe and fittings for only potable water applications and a small number of plastic materials, i.e. polyvinyl chloride (PVC), acrylonitrile-butadiene-Styrene (ABS) and polyethylene (PE). Over the 46 years since its development and introduction, NSF 14 has evolved into a plastic standard that is no longer restricted to potable water. It now covers a wide variety of applications such as DWV (drain, waste and vent), sewer, natural gas, industrial applications and reclaimed water. In addition, it covers a wide variety of materials such as polypropylene (PP), HDPE, Polyamide (PA), cross-linked polyethylene (PEX) and polysulfone (PPSU). This paper will specifically cover third party certification for HDPE pipe. It will address material, performance and quality control requirements.

A relatively simple method was proposed in a previous study for predicting the vertical behavior of tapered piles penetrating from the ground surface. This method uses the radial cavity expansion theory to model the increase in side resistance due to the radial ground expansion as a tapered pile is being pressed, and applies the second theory of the ultimate point bearing capacity proposed by Takano N. for the point resistance. Field press–in tests were conducted on four steel sheet piles and nine timber piles at a site mainly composed of silty layers. This paper presents the test results of these four steel piles and three timber piles including one straight–sided steel pile and one straight–sided timber pile. Pile resistance obtained from field tests is compared with the predictions made by the proposed analytical method. As expected, the shaft resistance increased with the increase in taper angle and the tapered piles offered a larger resistance than the straight–sided piles. It was also found that, on sites consisting of extremely soft soil, the penetration force–displacement relationships are very sensitive to the internal frictional angle of the soil.

Polyethylene (PE) pipes are often the material of choice for water supply systems, thanks to their favorable properties, such as high strength-density ratio and corrosion resistance. However, previous studies have shown that organic compounds can migrate from PE pipes to the water. This study aimed to identify potential organic compounds migrating from high-density PE (HDPE) pipes used to distribute drinking water in Denmark, based on laboratory experiments and sampling in the distribution system using a two-tiered study design.In the first tier, migration of volatile and semi-volatile organic compounds (VOCs and semi-VOCs) from HDPE pipes were investigated over one, three, and nine days in laboratory experiments, performed according to modified standards for migration testing (EN 12,873–1). The analytical workflow consisted of solid-phase extraction (SPE) for 10,000 times enrichment and gas chromatography – mass spectrometry (GC–MS) analysis from the water phase after migration. A total of 133 compounds originating from the PE pipes were detected. Thirty-one compounds were detected by suspect screening (SS), while the remaining 102 compounds were detected by non-target screening (NTS) analysis. Among the detected compounds were also hindered amine stabilizers (HALS), flame retardant, and plasticizer tris(2-chloroethyl) phosphate.In the second tier, drinking water from a water distribution system in Copenhagen, Denmark, with a newly installed HDPE pipe was sampled and analyzed with GC–MS and liquid chromatography high-resolution mass spectrometry (LCHRMS). A total of 51 compounds were detected in the water, 12 of which were assigned to migration from HDPE. Surprisingly, HDPE antioxidants and their degradation products contributed only a relatively small percentage of the total measured compound intensities in the drinking water distribution system. Instead, a larger proportion of the compounds detected were assigned to rubber seals, used upstream in the water system from the abstraction site to delivery at the consumer tap. Seals are considered trifle in the larger picture of materials in contact with drinking water, however these results may cause a reconsideration of this position.

Effect of temperature and loading frequency on the fatigue fracture process in high-density polyethylene (HDPE) pipe material has been investigated in this study via optical and scanning electron microscopy. Fatigue tests were performed using rectangular coupons obtained by slitting and flattening 50-mm-wide ring sections from 4-inch schedule 80 HDPE pipes. The flattening was carried out in a specially designed compression fixture at a temperature of 105 °C. Fatigue tests were conducted at temperatures of 0, 23, and 40 °C and loading frequencies of 0.1, 1, and 50 Hz. Fracture surface examinations reveal that the fatigue crack-growth process at all the test temperatures and loading frequencies involved mechanisms of shear yielding and crazing. Crack growth via crazing was found to be the dominant mechanism at higher temperature of 40 °C, while at 0 °C, a small amount of initial shear yielding precede the crazing process. Filler material particles contained in the HDPE pipe material play an important role of stress concentrators and help in micro-void nucleation, which promotes crack growth via crazing. The fatigue resistance of HDPE may thus be improved by addressing the stress concentration effect of filler particles.

With the increasing use of high-density polyethylene (HDPE) piping for nuclear applications, nondestructive evaluation is an important tool for evaluation of the integrity in fused joints. This paper will discuss the method of using ultrasonic phased array for inspecting butt-fusion (BF) joints in HDPE piping. The benefit of phased array is the ability to perform a volumetric inspection using multiple angles, which greatly increases the probability of detection of defects and allows the data to be analyzed using a representative two-dimensional image of the joint. It has been determined that successfully producing BF joints is highly dependent on environmental and mating-surface conditions. The primary defects of concern are lack-of-fusion, an area of the joint where there is no bond, cold fusion, an area of partial bond, and inclusion. Phased array has successfully demonstrated the ability of detecting and characterizing these defects using low frequency ultrasound. Factors addressed include joint location, wall thickness, material temperature, transducer wedge material, and manual versus automated data acquisition.