级班课程考试试卷考试科目考试时间学生姓名所在院系任课教师Karst tunnel technologyAbstract:Karst is a geological phenomenon, which is often encountered in Tunnel Construction.it will easily lead to gushing water excavation face suddenly mud, rockand supporting structure deformation, crack and collapse, the impact of the construction progress, endangering the safety of construction, the destruction of the surrounding environment. In this paper, the principle of the karst, explore the tunnels of different types of karst treatment, in addition, and the engineering example is introduced.Key words : Tunnel; Karst; Example projects1 OverviewKarst is an overview of surface water and groundwater for soluble rock (carbonate rocks, sulfuric acid rock, halogen salts, etc.) for chemical erosion, and the role of the collapse of mechanical damage, handling, formed by deposition of surface and subsurface erosion phenomenon known. Since then, we can see the definition : Karst have three major conditions : first, soluble rock Karst is the material basis. For example, the tunnel through limestone, dolomite, marl, and gypsum, mirabilite, rock salt and other strata, subject to possible ground water erosion, dissolved limestone in the main role. Dolomite mainly through infiltration - dissolution - decomposition - leaching-collapse occurred destruction. Second, the geologic structure and the formation of a vastly different set of karst types of diversity. Rock structure, structure and stratigraphic occurrence, exposure, thickness, fractured, folded, joints, fractures, weak layers, degree of weathering and other geological features of karst decision and magnitude different. Under normal circumstances, the syncline structure than anticline structure karst strong syncline structure of the nuclear karst strongly than wings, anticline structure than the two wings of the nuclear karst strong; When the tunnel through the Karst formation of joints, fractures, fault structure discontinuities, the easy solution gap encountered, control solution, caves, cavities or underground river. Third, the surface water and groundwater recharge, runoff, infiltration and the cycle is karst formation and development of the necessary conditions. Valley, depression, karst basins, shaft, funnel water sink in Liuzitian site, surface water pooling, infiltration, Stratum easily in the runoff with the horizontal and vertical seepage zone and stay with the deep, and the groundwater recharge cycle karst formation to create the necessary conditions for free when groundwater or erosion of CO2, SO4- the larger content, enhancing the development of karst.2001 started the Chongqing-Huaihua line length 624.523km, there were more than 20 tunnels Block 7km tunnel over which seven, the majority of tunnel throughthe karst carbonate strata encountered different sizes of the solution, caverns underground river, a number of water, mud sudden accident, construction to bring a lot of harm, on the environment to a certain extent, should arouse our serious attention.2 Tunnel on the principleAccording to the large number of karst tunnel construction and operation experience of the project, and in the light of relevant foreign Karst of literature, karst treatment should be followed to the main dredging, plug exhausting conditions, General principles of governance.Mainly to dredging is to try not to change the karst water runoff and seepage path, and maintain the original groundwater circulation and storage, thereby reducing the loss of groundwater to ensure construction safety and the environment, to build a green project objectives.Plugging row combination, in accordance with the tunnel Inflow size, silt content, and consider the operation of the tunnel safety and the environment, drainage and water shutoff will combine decided governance programs. Blocking or is likely to have for the working face of the emission of karst water or filling for plugging improve the mechanical properties of rock. rock permeability increase capacity and ensure safe and tunnel excavation after the completion of anti-leakage levels. But blocking is not the whole block, as long as the blocked tunnel of karst water infiltration to the main access road will be, Strengthening the scope of its general outline of the tunnel excavation lines (0.5) D. For larger dry cave or underground river, when plugging difficulties, can be taken in the construction of the external drainage tunnel or tunnels or the construction of culvert bridges across both reached the drainage purposes, ensures the safety of the construction and operation.Local conditions, comprehensive management, which is the tunnel under the engineering geological and hydrogeological conditions and the surrounding environment, adopt various methods in comprehensive fashion. For example, when a large amount of water was blocking the tunnel excavation outside, the right of partial leakage of water can take to the main block, limit emissions measures, and through the advance of tent Radial grouting and rock bolts and other aids in strengthening the rock top of the tunnel to prevent collapse; through replacement, bored piles, DJM, Christopher Pile, grouting methods reinforcement of the soft rock bottom, and enhance its overall strength, prevent basement settlement.3 Solubilization of water treatment3.1 connectivity method of SolubilizationIn order not to change the groundwater flow pattern, the dissolution of the water should be the first choice of treatment programs connectivity. Through various means of geological, proven solution of the tunnel around the development direction for the flow path clearer solution of water, If indeed dissolution of the tunnel will be cut off, through the vault, or the bottom sidewall appropriate location to increase the auxiliary channel solution of connectivity, Groundwater does not change the overall trend in mobile. As the general solution of water containing a large number of silt and may be affected by atmospheric rain, So such a pipeline supporting the one hand, there should be greater cross section, on the other hand there is a slope, prevent silt deposition.Ease of use advantages are : avoid using the first method of plugging various projects and the cost multiplied DELAY second, can prevent the tunnel surrounding water pressure increases, additional stress structure.3.2 the method of plugging groutingTunnel construction in karst areas, such as advanced exploration holes show working face in front of more development solution, When exploring water hole, water pressure and larger, in order to prevent water burst suddenly soil, in accordance with the dissolution of the development of location and direction Pregrouting using partial closure and the whole section Pregrouting sealing;If it is allowed to explore a water hole, water pressure or Q>20m3h P>1.0MPa. consider the use of full-face closure grouting.If it is allowed to explore a water hole stood out 10<Q ≤ 20m3h 0.5<P or ≤ 0.9 MPa pressure, consider the use of peripheral Pregrouting working face and for grouting partial closure.Explore how a water-hole stood out 2.0<Q ≤ 10m3h or pressure 0.2<P ≤ 0.5MPa. Excavation should be considered after peripheral radial grouting and local grouting, grouting added combination of methods for sealing.Pregrouting as working face of the construction and structural safety, appearance less affected, dissolution of the treatment, should first consider the whole process of excavation section Pregrouting surrounding pre-grouting, local grouting, added grouting program.3.3 Act emission limitsIf exploring water hole Q ≤ 2.0m3h P ≤ 0.2MPa. When able to identify drainage tunnel will not affect the construction schedule and the surrounding environment, the safety of adjacent buildings. disposal options available. But with the tunnel operators to extend the time for the tunnel behind the drainage system and the accumulation of silt more often plug especially in the freezing cold because of inflation, a more serious phenomenon, there are karst water emissions should be strictly limited.4 Cavernous processing4.1 Full-face closure grouting methodsIf the cave, larger internal filling a lot of silt, which is rich in underground water, once exposed, could occur suddenly the law of water, mud suddenly, the whole section should be employed pre-grouting reinforcement methods Grouting should be reinforced to tunnel excavation contour line 1-2 times the diameter, grouting long should take about 30m, Grouting diameter should be "90mm~108mm, grouting pressure on the termination of the water pressure should be 2-3 times serous 0.5~2.0m radius of proliferation. Under pressure, only the first cycle of concrete slurry wall thickness for 2471a. Grouting under pressure size hole ease, Soletanche usedback-grouting and installation of sub-orifice forward-grouting, grouting material may choose to use cement-water glass slurry and the average liquid slurry, grouting after grouting test results When the excavation reached at the request of each cycle can25~27m excavation, as the only remaining 5m slurry wall. If there is weak after excavation site, or using a short length of pipe Local added grouting.4.2 the method of replacement groutingAs for the water tunnel face powder compact sand or clay, sand clay, using permeation grouting, compaction grouting, Splitting grouting are very difficult times, use replacement grouting, grouting in the tunnel face for the project, grouting holes at a distance of about 2m set aside a few holes and install drainage pipe and valve orifice to remove silt appropriate, with serous filling the gap left their play reinforcement stratigraphic purposes. This method can reduce the grouting pressure, and promote the proliferation of serous.4.3 Filled closedIf Tunnel Arch, or the bottom sidewall small dry cave or cavity, the internal almost infill, anhydrous, they can aggregate, Inquire stones, dry-laid stone tablets, cement mortar and concrete aggregate thickness all filled, when necessary for grouting reinforcement. If the cavity of a small amount of water flow, it should not be filled completely blocked off groundwater water channel.4.4 substrate processingIf the bottom of the tunnel loose soft plastic or clay-like sand or clay sediments, To prevent trains running process of the settlement structure, we should strengthen the base, Crossing the bottom of the treatment available grouting reinforcement replacement, pile method.a) basement replacementIf the basement cavity filling thickness of less than 2.0m (2.0m following is the bedrock of the city or stratigraphic) consider using replacement method for the choice of fill material made of mortar and stone, concrete and so on.b) basement grouting reinforcementIf the basement cave filling thickness of the tunnel following 2.0~10.0m Invert may consider strengthening grouting method. Drilling depth of about 393 3.0m, 2.0m of the hole spacing and selection of appropriate grouting of seamless steel tubes, diameter "76mm~108mm, grouting material to use an ordinary cement slurry or ultrafine. grouting pressure should not exceed 0.9 MPa, grouting and possession of the top Invert be linked Supporting to enhance the structural strength and stiffness.c) pile handlingIf substrate thickness reinforcement over 10.0m may consider bored piles, bored piles or other DJM reinforcement. Concrete reinforcement thickness and extent determined by the design units.7 Conclusions and Experience(1) Karst handling is a complex technology, be adapted to local conditions, comprehensive management. While treatment programs should be considered on the surrounding environment and the residents of production and life, and on the other, should be a radical, leave no troubles to ensure that the tunnel construction and operation safety.(2) Accurate, advanced geological prediction means for the treatment cave is very important. Currently, using geological drawings, digital imaging, and advanceddrilling, infrared, ground-penetrating radar, TSP202. CT acoustic means of working face in front of Karst and around the size, scale, development, filling of prediction, forecast, but domestic and international applications, the use of non-destructive methods for detection of karst, in principle, or detection methods, means and the detection accuracy of the results, the need to be further studied, rich and the development and perfection and advanced drilling is one of the most intuitive and effective democracy and the legal construction should pay close attention.(3) Karst should try to avoid dealing with the rainy season and heavy rain. Depth of the tunnel smaller, cavernous Inflow is often subject to the atmosphere than in the rain, under normal circumstances, The continuous rains surface several hours after the cave water had increased significantly; greater depth of the tunnel, caverns water and surface water may have some water contact. Therefore, even the sunny weather a few days (usually more than one week), the cave is a better time.本文源自/p-208752177.html翻译：隧道岩溶处理技术摘要:岩溶是隧道施工中经常遇到的一种地质现象,它容易导致开挖面涌水、突泥,围岩及支护结构变形、开裂、坍塌,影响施工进度,危及施工安全,破坏周围环境。