| For the reasons of history and geography, our country always be hit by floods. Therefore we need fine vertical seepage control technology to remove the quality-hidden danger. The history of vertical seepage control technology is more than fifty years and is almost forty years in our country. At first, the technology mainly is build concrete cut-off wall by pour concrete with slotting. The concrete cut-off wall which the thickness is 60cm ~ 120cm and cost more than 400yuan/m~2 is mainly be used in important architectural engineering. Its using in water conservancy facilities had be limited because of the high cost. Then with the development of thin concrete cut-off wall technology, the use of high press grouting technique and the invention of manifold-small diameter deep layer agitator-boring-pile seepage-cutoff technology, the cost can be reduced so the vertical seepage control technology has been used widely in water conservancy facilities. This paper prefers the manifold-small diameter deep layer agitator-boring-pile seepage-cutoff technique that is be used widely and most economical, and the high press grouting technique that be used widest to study. We compared these two kinds of techniques to give full play to their advantages. Both the study result and the produce application can prove that the composite technology is better than any single technique. This method starts new train of thought of vertical seepage control technology studies. 1. Research purposeThe purpose is find an economical and reliable working method to reinforce dykes and dams. On the base of the old technique's advantages,we combine the manifold-small diameter deep layer agitator-boring-pile equipment that the deepest working depth is 25m with high press grouting equipment and put forward a relevant technique to raise the suitable for complex stratum. 2. Main achievement and proved content(1) Main achievement1) Put forward a new train of thought that compared manifold-small diameter deep layer agitator-boring-pile technique and high press grouting technique for the first time and get the relevant technology.First we use manifold-small diameter deep layer agitator-boring-pile technique to form wall and link up it with the wall that formed by high press grouting technique nest. Then we will get the cement-soil wall which the entirety, steadily and watertight are all fine.According to the principle of forming wall, the working technology can be resolved into three-construction sequence. The first sequence is using manifold-small diameter deep layer agitator-boring-pile technique to form wall. That is agitating and spraying slurry at the same time when the drills are sinking or hoisting. The second sequence is location and makes holes. The third sequence is forming wall by high press grouting. Two construction steps form this sequence: first, put down pipes, link up two pipes, hoisting to spray slurry and grouting back on odd number holes in turn. Second, spray slurry to even number holes after the first sequence finished 24 hours. The technological process schematic illustration is in chart 1.Inslail waterWaterAddAgitateSlurry makingLowpresssluny [*** AgitateVbtical movingLocatio1LevelinSinkin Hoistin —"^jSlnrrvTJ Q. 3X z>FinaGrout33ss>.n3'X" 3' ■Qnine3 ■q3 tj3J nThe first constructionsequence (manifold-sma 11 diameter deep layer agitator)The second constructionsequence (Make holes)The third constructionsequence I (High press groutingChart 1. Technological process schematic illustration 2) We got ZCJ-25 manifold-small diameter deep layer agitator-boring-pile machine to increase the economy of the composite technology, deepen the working depth and improve the working ability. Main technical indexes are in Tab. 1.Tab.l Main technical index of ZCJ-25 deep layer agitator-boring-pile machineModelZCJ-25AgitatorThe number of agitator axle3 or 5External diameter of agitator blade (mm)350-470Total power of electric machine (KW)150Hoisting unitHoisting capacity (KN)200Hoisting height (m)30.3Seep of rise and descend (m/min)0.3-1.5Slurry making systemVolume of slurry making machine (L)800Volume of slurry storage tank (L)1600BW150 mortar pump age (L/min)22-100Production capabilityThe length of one reinforce unit wall (m)0.96 or 1.6Deepest depth of reinforce (m)25Efficiency (mVunit-each shift)150-200Weight (t)42(2) Proved content1) Compared with the similar technique both in home and abroad This technology has many advantages such as cost is low, effect isgood, construction efficiency is high, the construction quality is easy to control, do not need slotting and being little of pollution of the environment when be used in complex stratum. It will have a broad market prospect.2) The overall calculate of the equipmentWe conduct the theoretical research to overall scheme of technology,define the technical feature index of the machine and calculate the stability, the ground pressure, the main transmission and the elevate system. These studies have offered the theoretical foundation for detailed design of the equipment.3) Technical feasibility of the projectBoth the manifold-small diameter deep layer agitator-boring-pile technique and the high press grouting technique are mature technologies and the equipments are reliable. The fundamental tenet of new technical composition has not be changed though it use the new ZCj-25 manifold-small diameter deep layer agitator-boring-pile machine, so it is dependable.Through the analysis of the cement-soil structure and the craft of forming wall, we know that this technique can form the continuous cement-soil wall, which have fixed strength, enough water stability and enough impermeability. From the analysis of physical mechanics character of cement-soil such as unconfined compression strength, coefficient of percolation, long-term stability, frost-resistance and so on we can reach a conclusion that cement-soil can be used as the main material of seep proof screen. The deepest depth is 50m and the minimum thickness index can meet the needs of design standard.4) Economic feasibilityOnly few technologies such as fluid-pressure grab grooving method and high press grouting can be used in complex stratum. The composite technology has well steadily and economical so the market demand is great. Both the direct and indirect economic benefits are good.5) Proved environmental impactThrough the application of the composite technology there are no water pollution, only slight air, noise and vibration pollution and limited effecting of traffic. The effecting of environment is slightly.3. New pointThe composite technology can be used in complex stratum and lower the construction cost. It has new point as follows:(1) Compared manifold-small diameter deep layer agitator-boring-pile technique and high press grouting technique for the first time both at home and abroad.(2) Gets the ZCJ-25 machine to improve the manifold-small diameter deep layer agitator-boring-pile equipment, using bit interlocking to form wall by one time. It can guarantee the overlap quality of unit wall.(3) The deepest working depth of ZCJ-25 machine has been raised to 25m and the power has been raised to HOkw. The construction ability is twice as much as before.4. Theoretical significance and practical value(1) Theoretical significanceThere are many vertical seepage control technologies in our country such as manifold-small diameter deep layer agitator-boring-pile seepage-cutoff technique, grab grooving technique, high press grouting method, vibrating and sinking molding board method, saw teeth grooving method and so on, but they all have the limits applicable. We combine the manifold-small diameter deep layer agitator-boring-pile technique with high press grouting technique and add a new dependable and economical choice of impermeable wall's building.(2) Practical valueDykes and dams in our country always be built on alluvial plain, which the surface layer is thin, the lower level is thick and the water permeability is well. To make sure that the dykes and dams are safe is an important work during the tenth and eleventh five years plan.At present, some dykes and dames cannot be built by manifold-small diameter deep layer agitator-boring-pile seepage-cutoff technique for the complex soil stratums and using fluid-pressure grab grooving method or high press grouting technique is too expansive. Some soil stratum relative watertight layer are too thick(30m~50m) to use the old technique.The composite technology is fit for these circumstances. It can be used in complex stratums and the effect is good. The construction efficiency is high, has little effecting of environment and cost low. This composite technology can meet the needs of building impermeable wall and cut down expenses for our country. It has great social and economy value. 5. Conclusion(1) The composite technology, which contains manifold-small diameter deep layer agitator-boring-pile seepage-cutoff technique and high press grouting, can be used in complex stratum. The construction efficiency of the composite technology is high. It has little effecting of environment and it cost low.(2) We got the ZCJ-25 machine, which can ensure the construction quality and increases the construction efficiency. The deepest working depth is raised to 25m, adds the dependable and economical of the composite technology. |
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