Experiment and Simulation Analysis of the Pressure Carrying Capacity of X80 Pipe with Metal Loss Defect on the Girth Weld

In order to study the pressure carrying capacity of X80 pipe with metal loss defect on the girth weld the water-pressure blasting test of the pipe with metal loss defect was analyzed by experiment and finite element simulation. Based on this, the sensitivity analysis of the factors affecting the pressure carrying of the pipeline, such as the circular size, the axial size, and the depth of the metal loss defect, was carried out. The research results show that the circular size of the metal loss defect on the girth weld had little impact to the pressure carrying capacity of the pipe while it reduced with the increasing of the axial size and the depth of the metal loss defect.

Experimental Study of Steel Reinforcement Repair Sleeve on X80 Pipe with Interlayer Defect

This paper introduces characteristics of common repairment method for oil and gas transmission pipeline, especially for steel reinforcement repair sleeve. In this research, an X80 pipe with interlayer defects repaired by steel reinforcement repair sleeve was studied. In order to investigate the repair effect of steel reinforcement repair sleeve for interlayer defects, a hydraulic blasting test and metallographic analysis for repaired pipeline were performed. The result shows that interlayer defect influences the pressure capacity of pipe to a certain degree, however, steel reinforcement repair sleeve could provide an acceptable strengthening to the repaired section.

Study on Numerical Simulation of Geometric Elements of Blasting Funnel Based on PFC5.0

Based on the particle flow code (PFC2D) within the discrete element method (DEM), the rock mass model was established according to the site rock conditions and the rock mass blasting was simulated by the explosive particle expansion method. The influence of various parameters (the peak pressure action coefficient of the borehole wall, explosive particle buried depth, and charge mode) in the explosive particle expansion method on blasting effect was investigated. Furthermore, the relationship between the various parameters and the geometry size of the blasting crater was obtained. By comparing the size of blasting crater in the field blasting test and numerical simulation example, the reliability of rock mass blasting simulated by the explosive particle expansion method using PFC is verified. The result shows that this paper provides a reliable new numerical simulation method for rock mass blasting and can be used to guide field blasting.

Influence of the Ammonium Nitrate(V) Porous Prill Assortments and Absorption Index on Ammonium Nitrate Fuel Oil Blasting Properties

Ammonium nitrate fuel oil (ANFO) samples, which were obtained by blending two different types of ammonium nitrate porous prills (i.e., AN-PP7 and AN-PP8) with fuel oil (FO) were studied. Measurements of structure, crystallinity and morphology were performed using X-ray Diffraction (XRD), Infrared Spectroscopy (IR) and Scanning Electron Microscopy (SEM), respectively. From the SEM analysis, it was indicated that a “wrinkled” structure characterized the crystal surface of the samples, which were based on two types of ammonium nitrate porous prill. Thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) confirmed that AN-PP7 had a higher absorption index in comparison to AN-PP8. Furthermore, it was shown that continuous AN phase transformations at precise temperatures took place. From the blasting test, it was indicated that the absorption index only had an influence on the content of toxic fumes. However, the velocity of detonation (VOD) depended solely on the ANFO density as well as the total volume of post-blast fumes.

Hydraulic Burst Test of X52 Pipes With Defects or Nozzle Repair Structure

Hydrostatic blasting test can be used to verify the bearing capacity of the pipeline in service. Spiral weld cracks and dents are common defects of pipes, and nozzle repair is a common repair method of perforated pipes. In order to determine the carrying capacity of the X52 pipeline with the above defects and the repaired structure, the corresponding pipe specimens were tested by hydraulic experiment, the yield pressure and burst pressure were recorded for each case. The axial and circumferential strains of the defect and repaired structure were measured in detail, the wall thickness and perimeter of the specimen before and after the experiment were measured, and the failure mechanism was analyzed. According to the relative safety factor in the standard, the bearing capacity of the pipeline was determined.

A Method for Making Transparent Hard Rock-Like Material and Its Application

At present, a similar material most commonly used in the similarity model experiment of rock blasting is cement mortar. However, it is not transparent, which leads to the problem that the cracks in the model made of cement mortar after the test cannot be observed directly. Therefore, a kind of transparent hard rock-like material that can replace the existing model material to solve the above problem was developed in this study. This transparent hard rock-like material is made of a mixture of rosin saturated solution (RSS), epoxy resin (ER), and curing agent (CA), and its physical and mechanical properties are similar to those of hard rock through relevant tests. In addition, it is found through the blasting model test that the model specimen made of transparent hard rock-like materials has the characteristic of “direct observation” after blasting test, which conforms to the rock blasting fracture mechanism. Hence, it can replace the existing nontransparent model materials to be applied in rock blasting similar model experiment. The results from this study are helpful to the further experimental study of blasting crack propagation in deep rock mass.