Optimization of artificial ground freezing applications. The turnback tunnel of guangzhou metro line 3 tianhe station with a large span was excavated in sandy clay which may easily break and disintegrate. The complexity of artificial ground freezing applications requires the use of numerical analysis tools to describe and solve the specific boundary value problem. Artificial ground freezing in geotechnical engineering. The company has made a major contribution to perfecting the ground freezing process. The transport and mechanical properties of saturated soil drastically change when temperatures drop below the freezing temperature of water. Us20040168460a1 method and apparatus for artificial. Thermal stabilization of ground helps to solve the problem of permafrost thawing under buildings and structures. Approach the analysis implemented in this paper, is based on geological and geotechnical reports with description of mechanical and thermal properties of soil. Along the groundwater flow direction, freezing wall forms slowly and on the upstream side the thickness of the freezing wall. Computer simulation of artificial ground freezing computer simulation with the help of computational methods, such as finite element method, finite difference method, and finite volume method, enables prediction of the behavior of objects like buildings, gas wells, road embankments, pipeline supports, etc. There are numerous ways and technique of soil stabilization for deep excavation or tunneling. A ground freezing method and system which circulates refrigerated heat transfer fluid through freeze pipes in the ground at a low temperature of at least.
The knowledge of the insitu temperature distribution is the key. Each white lump marks the top of a deep ground freezing tap. Thermohydromechanical modeling of artificial ground. This pa per presents the mechanical performance of the artificial ground freezing applied to shield tunneling in the construction of the. Modeling artificial ground freezing for construction of two. Artificial ground freezing is a construction technique utilized in poor ground conditions andor high water inflows. Jul 19, 2015 installation of 260meter deep freezing wells. It is often used to provide support for excavations or to cut off ground water seepage, although it can be used for applications such as the confinement of hazardous materials in the ground and creating impermeable. Us67969b2 method and apparatus for artificial ground. The engineering freezing method becomes possible with the development of refrigeration technology which has already been applied to projects such as mines, inclined shafts, tunnels, subways, bridge culverts, building foundations, etc. Artificial ground freezing is a construction technology that involves running an artificial refrigerant through pipes buried underground.
Artificial freezing of thawed and frozen soils by seasonal cooling devices has. Artificial ground freezing is a construction technique that is used in the construction of shafts, mines and tunnels to provide temporary earth support and groundwater control when other conventional methods such as dewatering, shoring and grouting. Nov 27, 2015 artificial ground freezing technique up to 1200 meters deep duration. Along the groundwater flow direction, freezing wall forms slowly and on. Ground freezing is also adopted as a temporary measure for the part b tunnel to strengthen the ground conditions around the tunnel for its construction. The concept of ground freezing was first introduced in france, and industrial applications date back to 1862 where it was used as a mine shaft construction method in south wales schmidt 1895. Numerical simulation of energy consumption of artificial. Artificial ground freezing technique up to 1200 meters deep duration. Simulation of heat and mass transfer during artificial ground.
The modeling of artificial ground freezing in geotechnical engineering applications has two main objectives, the first is the prediction of the extent of the frozen zone around the cooling sources thermohydraulic models and the second is the prediction of the grounds deformations and the site stability thermohydromechanical models. In this paper, the authors propose an efficient numerical model to analyze heat transfer during the whole excavation process for which this agf. Therefore numerical simulations have been carried out at the institute of geotechnical. Artificial freezing of thawed and frozen soils by seasonal cooling devices has become widely spread in permafrost in the far north. The artificial ground freezing agf technique was used to stabilize the soil and to prevent its collapse during excavations. Most of the existing theoretical analysis and numerical simulation on the agf technique are purely based on a.
The construction includes a junction of main tunnel with a ramp way that connect underground tunnel route to the ground surface. This paper describes artificial ground freezing technology, discusses its engineering properties, illustrates its applications in geotechnical engineering, and concludes with a brief summary of various artificial ground freezing project experiences. Artificial ground freezing agf method was firstly applied to provide a safety condition of intake installing construction, which played a role of water sealing and. To increase the regular application of the artificial ground freezing method not only the freezing time but also the energy consumption has to be reduced. Introduction with increasing demand of good water barrier and nonpollution characteristics, artificial ground freezing agf method is particularly widespread in environmental. Modern methods such as liquid nitrogen and efficient refrigeration compressors have dramatically lowered temperatures, resulting in greater frozen ground strengths, reduction in the time taken for the freezing process and considerable cost savings. The potential problems of agf include surface heaves due to expansion of the frozen soil or settlements due to consolidation in the thawing phase. The thyssen group has used this ground stabilization method for over 100 years with the first artificial ground freeze project having been completed in 1905. Numerical simulation of freezing pipe deformation during artificial ground freezing article pdf available january 2019 with 15 reads how we measure reads.
Artificial ground freezing method, saline groundwater, freezing point, solute exclusion, frozen barrier. One of the most important factors is ground water flow, which. It should be noted that it is essential that groundwater be present, supplied either by high water table or artificially. Development of ground freezing system for undisturbed sampling. Monitoring and evaluation of artificial ground freezing in. Optimization of artificial ground freezing applications aim of the research project a systematic use of the ground freezing method often fails due to the energy costs that are expected to be excessively high. Artificial ground freezing has been used for many years to freeze selected areas of the ground for a number of different purposes. Ground freezing application of intake installing construction of an. In this study, application of freezing in shield tunneling is investigate. A case study of a comprehensive underground tunneling project in tokyo suburb is considered. The artificial ground freezing agf system is widely used in underground mines, shaft sinking, civil, and tunneling applications for stabilization of underground. Therefore it is necessary to take into consideration the operating phase which essentially affects the total energy. Aquarius project artificial ground freezing in timmins, ontario water table was high and the site was rich in gold concentration. Most of the existing theoretical analysis and numerical simulation on the agf technique are purely based on a couple of.
Methods, applications and advantages of ground freezing is discussed. Instead of conventional grouting method, artificial ground freezing is selected as the ground treatment for tbm breakthrough. The aim of the current research is to evaluate the feasibility of artificial ground freezing applied to the current case. The model to be developed should be capable of predicting the structural as well as the thermal processes involved in the freezing application. Its principle is to circulate a fluid refrigerant ca. Ground freezing allowed tunnels to be excavated under an active railyard during bostons big dig.
Studying the artificial ground freezing method with. An artificial ground freezing agf technique in the horizontal direction has been employed in naples italy, in order to ensure the stability and waterproofing of soil during the excavation of two tunnels in a real underground station. Modeling heat and mass transfer during ground freezing. Especially in the case of artificial frozen ground, natural or induced groundwater flow may have a strong impact on the development of the frozen conditions. Each white lump marks the top of a deep groundfreezing tap. Artificial freezing of thawed and frozen ground by seasonal cooling devices has become widely spread in permafrost zone in the far north. Numerical simulation of artificial ground freezing. The system, since then, has been used intensively in several applications such as underground mines, shaft sinking, civil and tunneling, maintaining the permafrost structure by implementing thermosyphon concept, and. Pdf artificial ground freezing of fully saturated soil. Artificial ground freezing for rehabilitation of tunneling shield in.
The artificial freezing technique consists of letting a coolant fluid, with a temperature lower than the surrounding ground, circulate inside probes. Cross section of a ground freezing pipe as used in the big dig. As for artificial ground freezing, it has a broad range of applications, from tunnels to landslides stabilization through shaft sinking and containment of hazardous waste. Controlled ground freezing for construction and mining applications has been in. Ground freezing in construction ground freezing in construction artificial ground freezing is a construction technique that is used in the construction of shafts, mines and tunnels to provide temporary earth support and groundwater control when other conventional methods such as dewatering, shoring and grouting or soil mixing do are not feasible. Computer simulation of artificial ground freezing during the building of underground tunnel in germany, during the construction of a new intersection between the regional carrier, deutsche bahn, and a city underground railway line, a new railway section with a total length of 1. Artificial ground freezing in tunnelling through aquifer soil layers. Ground freezing is a construction technique used in circumstances where soil needs to be stabilized so it will not collapse. Ground freezing is a soil stabilization technique carried out by continuously refrigerating the soil. Pdf artificial ground freezing application in shield tunneling.
Pdf numerical simulation of freezing pipe deformation. The application of tried and tested technologies of artificial ground freezing and cooled air forced ventilation lends itself to solving a problem on the scale of cooling the deep tube network in london, meeting the aims set out by the iea as a sustainable use of underground thermal energy storage. May 18, 2017 artificial ground freezing is a construction technology that involves running an artificial refrigerant through pipes buried underground. Computer simulation of artificial ground freezing during the. Effects of material and drilling uncertainties on artificial. Artificial ground freezing application in shield tunneling. Artificial ground freezing is the most universal and safest way to increase ground strength. Intermittent freezing concept for energy saving in artificial ground.
Artificial ground freezing technique up to 1200 meters deep. Artificial ground freezing agf was developed by friedrich poetsch in the 19th century to stabilize the construction of deep shafts in saturated soil. Mar 31, 2014 artificial ground freezing agf is a soil stabilization technique involving the removal of heat from the ground to freeze a soils pore water. Accordingly, the freezing rate j can be replaced by j. Dec 12, 2017 the artificial ground freezing method can be used jointly with the deep cement mixing method during breakin and breakout processes of shield machines in a tunnel shaft. As the refrigerant circulates through the pipe network, heat is removed from the ground and ice begins to form around the pipes. Conjugate heat transfer in artificial ground freezing using. Manual sounding was performed by sounding in points. Pdf artificial ground freezing for rehabilitation of tunneling. Simulation of heat transfer during artificial ground freezing. To extract gold, while preventing inflows of groundwater to the mine excavation, a frozen earth barrier was constructed around the perimeter of the aquarius open pit gold mine. Case studies of artificial ground freezing simulations for. The heat transfer fluid is preferably aqua ammonia ammonium hydroxide because of its beneficial characteristics in this application. Artificial ground freezing of fully saturated soil semantic scholar.
Thermal stabilization of ground by its passive refrigeration helps solve the problem of permafrost thawing under. Numerical simulation of soil stability during artificial freezing. Mine shaft freezing pdf gsz page 1 of 9 mine shaft freezing 1 introduction artificial ground freezing is used in many engineering projects to excavate and construct mine shafts, tunnels or other underground structures through water bearing, often unstable, ground formations. Numerical simulation of artificial microswimmers driven by marangoni flow nitrous oxide emissions from soil during freezing and thawing periods on spurious water flow during numerical simulation of steam injection into watersaturated soil. Method and apparatus for artificial ground freezing layne. Artificial ground freezing technique for tunnel stabilizing. The artificial freezing technique consists of letting a coolant fluid, with a temperature lower than the surrounding ground, circulate inside probes positioned along the perimeter of the gallery. Computer simulation of artificial ground freezing frost 3d. The artificial ground freezing method can be used jointly with the deep cement mixing method during breakin and breakout processes of shield. Artificial ground freezing agf is a soil stabilization technique involving the removal of heat from the ground to freeze a soils pore water.