The new method of reinforcing deep soft base-concrete core sand stone mar compound foundation method
Technical field
The present invention relates to a kind of method for processing foundation, especially a kind of reinforcing and processing method of high-moisture high organic content deep soft soil foundation, specifically a kind of new method of reinforcing deep soft base-concrete core sand stone mar compound foundation method.
Background technology
Soft-soil foundation treatment method mainly contains preloading, dynamic compaction, cement mixing pile, powder spray piling, compacted sand-gravel pile, CFG stake, cast-in-place thin-wall pipe pile, prefabricated tubular pile compound foundation method etc. at present.Wherein, piling prepressing discharging consolidation method easy construction, expense are low, but exist the reinforcing phase long, settlement after construction is big, in work progress for guaranteeing that base stabilization needs problems such as the loading velocity requirement are tight; Dynamic compaction exist to lack ripe design and calculation method, ruggedized equipment and rams that energy is little, reinforcement depth is shallow (generally about 10m), problem such as constructional difficulties, consolidation effect difference when groundwater table is high; Cement mixing pile and powder spray piling are cheap, construction technology is comparatively ripe, and reinforcement depth shallow (general unit in charge of construction quality can guarantee that the degree of depth is in 12~14 meters), match ratio and construction technology must in time be adjusted according to geological conditions,, problem such as construction quality wayward strict to unit in charge of construction's technical level but exist; Problems such as stake poor continuity when compacted sand-gravel pile exists natural weak soil intensity low, bearing capacity are little; Problem such as bottom poor continuity when stake was longer when immersed tube pore-forming CFG stake existed natural weak soil intensity low, there are problems such as ruggedized equipment is few, output investment ratio immersed tube pore-forming CFG stake high about 10% in long spiral pore-forming CFG stake; There is the quality examination difficulty in cast-in-place thin-wall pipe pile, invests problems such as big; The prefabricated tubular pile existence runs into hard interbedded layer and penetrates difficulty, invests problems such as big.On the whole, the reinforcing of discharging consolidation method ubiquity is long in time limit, settlement after construction big, require problems such as tight to banketing; Problem such as low-intensity pile composite foundation method ubiquity quality control difficulty, reinforcement depth are shallow; Then there are problems such as investment is bigger in the compound ground method of high strength, so these methods all have its scope of application.
Summary of the invention
The purpose of this invention is to provide a kind of in conjunction with consolidation to the consolidation effect of weak soil own significantly and precast concrete pile intensity height, quality control the concrete core sand stone mar compound foundation method of both advantages easily.
Technical scheme of the present invention is:
A kind of new method of reinforcing deep soft base-concrete core sand stone mar compound foundation method is characterized in that it may further comprise the steps:
A, employing vibration sinking tube or long spiral way form installing hole on soft foundation;
B, the prefabricated single or some prefabricated concrete stakes that connect while placing less than the aperture of the installing hole of above-mentioned gained of maximum outside diameter size are positioned in the described installing hole between two parties;
C, perfusion has excellent permeability in space around described installing hole and the concrete stake sand and/or stone fragment, limit vibration pipe-drawing limit material filling makes the sand of perfusion in the hole and/or rubble form the draining shell of stake through vibratory compaction, thereby obtains concrete core sand stone mar;
The quantity of the concrete core sand stone mar that d, repetition a, b, c bury underground on the soft foundation of reinforcing at need meets design requirement;
E, lay and the suitable mattress layer of soft foundation area that needs to reinforce at the top of concrete core sand stone mar, described concrete core sand stone mar promptly constitutes composite foundation of the present invention with described mattress layer, forms drainage channel between concrete core sand stone mar and mattress layer.
The present invention has also further taked following technical measures:
1, make the upper surface of described concrete core sand stone mar apart from 20~50 centimetres on ground, and make and form a reverse taper hole between the top of concrete core sand stone mar and the ground, in described reverse taper hole, pour into sand and/or rubble and compacting, formation prevents that prefabricated concrete pile body produces the sand stone layer of thrusting destruction upwards under the upper load effect, lay mattress layer then on sand stone layer top, the draining shell of concrete core sand stone mar, sand stone layer, mattress layer mutual group become drainage channel.
2, described sand can be pure medium coarse sand.
3, described mattress layer can be sand or rubble mattress layer, and its thickness is 40~60 centimetres.
4, be provided with two-way geogrids layer in described mattress layer, the soffit of mattress layer contacts with sand stone layer in the described reverse taper hole.
5, described prefabricated concrete stake or be cylindrical or square, the internal diameter of described installing hole should be greater than the external diameter of cylindrical concrete stake or the cross section catercorner length of square concrete stake, and the space between installing hole hole wall and the prefabricated concrete stake outer wall placed in the middle is not less than 10cm.
Beneficial effect of the present invention:
Prefabricated concrete stake of the present invention mainly plays bears vertical load and it is passed to down hardpan effect for sleeping in, owing to be prefabricated, quality is controlled easily, thereby make concrete high strength be not fully exerted, thereby can reach the bearing capacity of single pile of pile strength control and the single pile bearing equilibrium of forces of pile side friction control (mainly by the control of sidewall frictional resistance, concrete strength wastes 30~50% to the bearing capacity of single pile of common friction-type concrete stake); The sandstone shell that is tamped around the concrete stake of the present invention mainly works core pile sidewall friction force and the vertical drainage effect of strengthening, and weak soil because of descending, is recovered strength of turbulence rapidly, sharing the super quiet hole of banketing behind the load in the inter-pile soil, ground presses rapidly and dissipates, dissipation speed is generally about 18 times in the common plastics plate consolidation, inter-pile soil intensity improves rapidly, and the bearing capacity of stake increases along with the depth of fill and significantly improves; Owing to needn't resemble vertical carrying the sand compaction pile, so require needn't be too high for the compactness of arenaceous shell, common vibratory compaction or perfusion pressurize closely knit all can, thereby convenient and quick construction.Simultaneously concrete core sand stone mar of the present invention need not maintenance, can save the curing time before detecting when engineering is used.
Description of drawings
Fig. 1 is the structural representation of concrete core sand stone mar of the present invention.
Fig. 2 is the structural representation of composite foundation of the present invention.
Fig. 3 is a concrete core sand stone mar composite foundation structure generalized section of the present invention.
1 is prefabricated concrete stake among the figure, and 2 are the draining shell, and 3 is the back taper sand stone layer, and 4 is geogrids layer, and 5 is the sandstone mattress layer, and 6 is concrete core sand stone mar, and 7 is top preloading layer.
The specific embodiment
The present invention is further illustrated below in conjunction with accompanying drawing and example.
As shown in Figure 1, 2, 3.
Specific operation process of the present invention is:
(1) stake position setting-out: arrange stake position (being the position of installing hole) by the design scheme requirement.
(2) pile-forming machine perching: the stake machine moves to pre-piling position, center, immersed tube centrally aligned stake position, and it is perpendicular to the ground to adjust immersed tube, guarantees that perpendicularity deviation is not more than 1%.
(3) immersed tube: starter, immersed tube is shut down to predetermined absolute altitude.Starter vibration loading when meeting hard interbedded layer is until penetrating hard interbedded layer.Adopt vibration sinking tube (it is generally weak to be applicable to that ground does not have hard interbedded layer, weak soil soil property) or long spiral (being applicable to that ground has very weakness of hard interbedded layer or weak soil soil property) mode pore-forming.
(4) put into prefabricated concrete stake 1: immersed tube utilizes after the projected depth hoist engine prefabricated concrete stake 1 to be sling and by the hole in the middle of two vibrating hammers the steel pipe center is put in first prefabricated concrete stake 1 from tower top and fixes, and puts into the hole subsequently slowly.When treating that pile crown bassets 50~60cm, insert from the pile body preformed hole with a bar reinforcement that is about 80cm and to cross, take, place in the hole pile body is unsettled, so that pile extension in the firm position of stake pipe.
(5) pile extension: be connected pre-embedded steel slab flange, sulphur spring clay, welded connection or other effective means spreading that adopts routine between stake and the stake.
(6) feed intake, tube drawing: pile body is all put into hole back spud pile in center, position, hole, utilizing near the pipe top dog-house to pour into pure medium coarse sand or stone fragment enriches and pushes up until stake, starter stays the 5~10s that shakes, begin tube drawing then and open the sharp flap valve door of stake, tube drawing limit, limit vibration (adopting segmentation to stay in case of necessity shakes) forms the concrete core sand stone mar 6 that has draining shell 2 in ground.Pipe-pulling speed should be controlled at about 1.2~1.5m/min by at the uniform velocity control.Repeat above-mentioned steps and continue next root construction.
(7) treat to lay the sandstone of geo-grid 4 and the thick 40~60cm of being as mattress layer 5 at the top of stake after whole concrete core sand stone mar 6 constructions finish.Lay half storey sand-gravel cushion down earlier, lay two-way geo-grid 4 after the leveling compacting, lay then and go up the half storey sand-gravel cushion, all concrete core sand stone mars 6, geo-grid 4 and up and down two half storey sandstone mattress layers 5 constituted composite foundation of the present invention, the draining shell 2 of concrete core sand stone mar 6, geo-grid 4 and up and down two half storey sandstone mattress layers 5 formed the drainage channel that connects simultaneously between them.
For preventing that prefabricated concrete stake produces the destruction of thrusting that makes progress under the upper load effect, can control the stake top behind the pile and be lower than ground 20~50cm, can form than the big slightly cone-shaped groove of concrete core sand stone mar 6 diameters on pile crown top with artificial finishing a little back, pour into the sandstone compacting and form back taper sand stone layer 3, lay the sandstone mattress layer 5 of thick about 40~60cm and 1~2 layer geo-grid 4 subsequently, concrete core sand stone mar 6, sand stone layer 3, sandstone mattress layer 5 and the geo-grid 4 that is arranged in the sandstone mattress layer constitute the more perfect composite foundation of the present invention together, the draining shell 2 of concrete core sand stone mar 6, sand stone layer 3, sandstone mattress layer 5 and the geo-grid 4 that is arranged in the sandstone mattress layer form the more complete drainage channel of the present invention, as Fig. 2, shown in 3.Prefabricated concrete stake can be circle, also can be square (as Fig. 1), about the about 20cm of diameter, is of a size of 20cm * 20cm when square when its size is generally circle.