The invention relates to a method for placing a concrete-structure load-bearing pile or anchoring pile into the ground, in which method another device, like with an end piece equipped tube is forced by means of a hammering device into the ground to an intended depth and to a place meant for the intended pile, after forcing concrete mass is lead into said tube and simultaneously the tube is drawn out of the hole by means of the hammering device wherein concrete mass fill the space meant for the final pile and the end piece remaining as a pile top.
Earlier is known the method according to the preamble from patent publication EP 1134319 B1, in which publication in addition to the above a sealed end piece is presented said piece connected to the tube which is forced into the ground, said end piece prevents water entering into said tube in water content ground. The tube is forced into the ground by means of a vibrating device which impacts in the upper end of the tube. The concrete mass is cast into the tube which is simultaneously drawn up from the ground.
As a disadvantage for the above described method is that of its body high and heavy pile hammering device is needed, said device further has mass concentration in its upper end so, that only vertical tubes or very little tilted 5-10° tubes can be hammered into the ground. Tube is possible to be drawn up by means of this kind of device only if the hammering device is such a vibrator being able to change the hammering direction. Inclinedly locating anchoring piles and inclined supporting piles are not possible to manufacture by means of this kind of method. Further this kind of from the top hammering pile driver needs space in the vertical direction remarkable more than what is the height of the pile, which has importance when worked under hinder, like bridges. The from top hammered or vibrated piles also try to turn due to in the ground met hinders, disturbing pieces or inclined layers easily to inclined direction and the pile becomes as inclined pile. This pile has not the same load bearing ability than the vertical pile has and it also needs more reinforcing steels.
Further is known forcing of the ready concrete pile into the ground, wherein to its upper end is hammered generally by means of a drop hammer. As a disadvantage for this pile is that its load bearing ability cannot be added after hammering into the ground. When forced into the ground it bears load by means of the front piece and pile side friction. It must be hammered so deep, that desired load bearing is formed by means of these two frictions when it acts as a load bearing pile or desired pulling resistance is formed, if it has been intended to be an anchoring pile. The load bearing capacity can be estimated by means of the produced advance due to the drop hammer at each moment.
The needed pile driver is also in this case remarkable higher than the pile and heavy and the ready piles must be forced essentially in vertical direction into the ground. Disadvantage for this ready pile is that it may break during forcing, because great hammering hits are directing to it, said hits producing respectively great opposite vibrations back which vibrations may break the pile made of concrete. In some cases this pile needs reinforcing steels only when hammered into the ground, no more when being as a load bearing pile, wherein the steel reinforcements are useless additive charge.
Due to in the above described known methods existing weaknesses and defects a new method has been developed, by means of which forcing of a concrete pile into the proper depth is solved, further essential increase of the load bearing and pulling resistance to get them bigger than what the hammering resistance was been during hammering as well as manufacturing the pile in different angles even in horizontal direction especially in anchoring meaning. Characteristic for the method according to the invention is, that it is generated to the pile load bearing ability or anchoring pulling strength increasing shapes in the pile front end or after desired distances by means of stopping or making slower the drawing up of the tube immediately in the beginning of the draw-up portion and allowing the concrete mass to form a widening portion in the pile front portion either for increasing the pressure of the concrete mass or for producing vibration to the tube and concrete mass or by using both above mentioned together.
Advantageous for the method according to the invention is, that the pre-hole for the concrete pile can be made very quickly by means of the into the ground forged and re-usable tube, because the tube has little side friction, wherein the tube penetrates into the ground easier than for example ready concrete pile. The quality variations in the ground become very well observed during forcing, because the front piece in the tube is essentially the biggest producer for the forcing resistance. In the place of the big forcing resistance in the ground the walls of the pile hole also become most strengthened. This strengthening acts advantageously also as buckling support for the pile. The received quality knowledge of the ground is utilized when searching locations for the shapes which increase the load bearing ability for the pile. Thanks to the side grip taken by the pile driver the pile driving can be made by means of the hammering device connected to an excavator, by which also the tube can be drawn up from the ground. Thanks to the vibration generated by the hammering device the flow of the concrete mass can be adjusted when the tube is lifted up from the ground. Pile driving needs space over ground surface only 2-3 metres more than what is the length of the pile to be forced into the ground. The pile can be mounted in vertical direction by means of side grip vibration better than when hammered from the top, wherein the need of the concrete reinforcement steels decreases.
The weight sounding belonging nowadays to the researching methods, by which weight sounding the load bearing ability and the length of the pile are concluded, can be excluded by using this method according to the invention when the advance of the first into the ground forced tube is observed. In other case if the weight sounding is carried out, the needed length of the pile according to this invention can be concluded.
By means of the invention essentially greater load bearing ability can be obtained for the produced pile, what can be estimated based on the forcing resistance of the tube. When the smooth forcing tube in this invention changes to a shaped, widening portions comprising concrete pile, essential increase in the load bearing ability is achieved as well as increase in the pulling resistance for the produced pile. These increases will multiple the load bearing or pulling resistance even 3-5 times compared with the respective ones of the smooth forging tube. It follows also, that the needed pile lengths will shorten or the pile distances from each other can be lengthened. The widening portions according to the invention can be made at the pile length in correct points, when during forging of the tube the strength changes in the ground is observed. By the method according to the invention also into the ground mounted vertical load bearing pile can be made, which has adjusted minimum cross-section area, for example side lengths 200 mm, and which pile as such a pile does not need reinforcement steels.
In the following the invention is closer described with reference to the accompanying drawings, where
In
In
In
In
The tube 1 is presented in
When the pile is ready and includes widening portions 8 as well as of concrete made indefinite side portion its load bearing ability has increased essentially compared with the ability which was obtained for the into the ground forced tube 1. The final load bearing ability for this kind of pile can be experimentally determined and based on the sufficient amounts of samples it is possible to determine, how the load bearing ability for the final pile can be obtained from the load bearing ability of the tube 1 when said tube acted as a pre-pile.
The manufacturing of the anchoring pile by the same method is presented in
Inside the tube 1 in
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI2009/000036 | 3/20/2009 | WO | 00 | 9/20/2011 |