Papers by Keyword: Underground Pipeline

Abstract: Underground pipeline systems in Thailand have been used for a long time. Lack of maintenances and longtime using cause a lot of damages. The water distribution systems are affected by the quality of water from contaminations and the quantity of water from leaking. As well as the sewer systems may flow through and contaminate the groundwater. Due to the long period of time of using underground pipeline systems, the verification of the underground location is need before testing the conditions of the systems with undisturbed area methods. This study focuses on the collection of the underground utilities locating methods and the conditions assessment methods. We also apply one suitable method for our case study area which is Nakhon Pathom province, Thailand. The results show the collection of methods to verify the underground location and conditions systems as well as the advantages and disadvantages of each method. Results also describe about conventional CCTV with push-rod camera for assessing underground pipeline systems for Nakhon Pathom province and the locations verification is fitted with ground penetrating radar, infrared thermography and acoustic location system. The design of a mobile robot to be flexible according to the pipe size and the creation of a computer program that can analyze the most suitable methods for examining buried pipes is a good option for further expansion in the future.

Abstract: A stress state of the partially damaged underground steel pipeline after reconstruction by means of the fiberglass composite material is considered. The strength properties of the composite are determined experimentally. The effective elastic moduli of the composite are determined by means of the finite element homogenization. Tsai-Wu failure criterion is used for the composite part of the pipeline. The influence of geometrical parameters and loading conditions on the safety factor of the pipeline is analyzed and discussed.

Abstract: With the expansion and modernization of cities, the intensity and density of urban underground pipelines are dramatically increasing, and the surrounding environment of the underground pipelines is more complex. This paper analyzed the environmental factors of the pipelines, and divided the environmental factors into soil environment, external force and natural disaster. By using the Accident Tree Analysis researched the basic events that cause the underground pipeline accidents, and the results shows that the most important basic events are the human constructions, without protective measures, and the second important basic events are corrosion failure, no timely detection and treatment of the environment risks, such as underground cavity, encroachment. The evolution mechanism of underground pipeline accident was analyzed. According to the analysis results, the soil surrounding the underground pipelines may be evolved into unstable-state under the influence of environmental inducements, finally the underground pipelines may be damaged and the accidents will happen without any protective measures.

Abstract: A model of risk trend assessment for metro tunnel crossing underground pipelines is proposed in this paper based on the partial connection number. This paper fully considered the certainty and uncertainty of the index and used "partial connection number method" to analyze the risk developing trend and its sort of metro tunnel crossing underground pipelines. A case study was performed on a metro tunnel engineering of Shenzhen Line 9. The results showed that this model considered the dynamic characteristics of risk, enriching the contents of risk assessment of underground engineering, which can provide a reference for the risk management.

Abstract: Shield tunnel construction cause soil movement to harm the adjacent underground pipelines. This paper, taking Dalian Spring Street subway station as the background, uses the finite difference software to establish 3-D finite element analysis model to simulate the deformation of pipeline with 45* skew angle in the tunnel construction work. The results show: when the left tunnel push towards pipelines, due to the skew of the pipeline and tunnel, vertical displacement of pipelines is a certain shift to the left. When the right tunnel excavation is complete, the pipeline maximum settlement has a return to the center of the two tunnels. The settlement of pipeline is much bigger than horizontal displacement.

Abstract: Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.

Abstract: Rationalization of modern tourist scenic spot planning is very important to the development of the whole scenic area, and the rational planning of tourism resources of scenic area is based on the full development of resources, then making the systems be optimized in the scenic area. When applying GIS technology to urban tourism scenic spot, the distribution of tourism resources will be more reasonable. The application of GIS network analysis function on traffic planning and underground pipeline planning, which achieve programming optimization, and then doing three-dimensional visualization for network planning, clearly analysis the planning rationality. The superiority of GIS spatial analysis functions makes the tourist scenic spot planning optimization in low-cost, and also provides a good platform for the operation and management of scenic area.

Abstract: Based on Dalian subway line 2 from Chun-guang street station to Xiang-gong street station,the three dimensional finite element model was established using FLAC3D software , the shield excavated surface against the pressure, the stress release, the shield tail escape and grouting. The numerical result indicated that the pipeline displacement increases gradually with the advance of the tunnel excavation. When one-sided tunnel excavation is carried out, the largest displacement is located at the tunnel axis, the settling curve basically conforms to the normal distribution curve with the unimodal characteristic. The excavation of right-side tunnel is disadvantageous to the left-side tunnel. The analysis indicated that the pipeline is in a secure state. The work in this paper provided theoretical basis and the practical guidance to this project.

Abstract: By collecting the data of the ground scene and non-destructive detecting of the underground pipe network, using freeform software design of the data collected by the three-dimensional color modeling and rapid prototyping systems will underground complex pipeline modeling, using ground-dimensional graphics and three-dimensional model of underground pipe network combined method, This paper is trying to find out an effective presentation method for the distribution of underground pipe network. Thus, an efficient, realistic, intuitive three-dimensional rapid mapping prototyping service technology corresponds to the ground and underground pipe network scenario is applied to urban planning, municipal infrastructure, scientific management, maintenance and reconstruction.

Abstract: Pit excavation influences the stress and deformation of adjacent underground pipelines seriously. On the base of former study, the project was analyzed with the aid of general finite element soft ABAQUS, in which the interactive action of soil with pipeline and pit protection structure were taken into account. Wall-soil friction and pipeline-soil friction contact were used. The influence on adjacent pipelines of pit excavation was analyzed. The laws of deformation and the stress were gained. The results showed that the horizontal displacement was much bigger than the vertical displacement, and the pipeline would lift at the end close to the symmetric plane and fall at the other end. The displacement would decrease with the increment of the distance between pit and pipelines. The laws of influence of the pipeline’s embedment and wall-soil friction were similar, while the latter’s influence was greater than the former’s. The influence on horizontal displacement aroused by wall-soil friction was greater. The principle tensile stress mainly aroused by the pipeline’s horizontal displacement would cause tension fracture. The sections of the pipeline around the area of the end and the middle of the pit were dangerous, which should be particularly protected.