CN203741824U - Rammed carrier strong core multi-component composite pile - Google Patents

Abstract

The utility model relates to a multi-element composite pile with a rammed expansion carrier and a core. The purpose is to provide a composite pile that has both the advantages of flexible piles and rigid piles, and has the advantages of good drainage effect and high bearing capacity. The technical solution is: a multi-element composite pile with a rammed and expanded carrier core, including a bulk pile vertically fixed in the soil layer and using construction waste as recycled aggregate; A rigid core pile formed of reinforced concrete; the bottom of the rigid core pile is flush with the bottom of the bulk pile, and the bottom of the rigid core pile and the bulk pile are also connected to a spherical carrier expansion head to form a rammed and expanded carrier strength core composite pile.

Description

A multi-element composite pile with rammed and expanded carrier core

technical field

The utility model relates to a multi-element composite pile reinforcement technology for soft soil foundations, in particular a composite technology based on loose piles, rigid core piles and tamping carriers, which is suitable for reinforcement of soft foundations with uneven stratum distribution or different bearing capacity requirements.

Background technique

In highway soft soil foundation treatment technology, the methods to improve the bearing capacity of piles in composite foundation include the following three methods: ① Increase the stiffness of the pile body to reduce the compression deformation, ② Increase the diameter of the pile body to increase the side friction resistance and ③ Increase the volume of the pile tip Increase the bearing area. Each of these methods has its own limitations, and the individual use will be restricted by various factors, so that the pile-soil interaction and its bearing characteristics cannot be maximized.

Utility model content

The purpose of this utility model is to overcome the deficiency of the above-mentioned background technology, integrate the technical advantages of bulk piles, rigid core piles and carrier piles, and provide a multi-component composite pile with a rammed and expanded carrier core; the composite pile has both flexible piles and rigid core piles. The advantage of the pile is that it has the advantages of good drainage effect and high bearing capacity.

The technical scheme provided by the utility model is:

A multi-element composite pile with a rammed and expanded carrier core, comprising a bulk pile vertically fixed in the soil layer and using construction waste as recycled aggregate; it is characterized in that a reinforced concrete concrete pile is vertically interspersed in the bulk pile Rigid core pile: the bottom end of the rigid core pile is flush with the bottom end of the bulk pile, and the bottom end of the rigid core pile and the bulk pile are also connected to a spherical carrier expansion head to form a rammed expansion carrier strength core composite pile.

The expanding head of the spherical carrier is composed of a construction waste packing layer covered by an external compacted soil layer and a dry hard concrete layer inside the construction waste packing layer.

The axis of the rigid core pile coincides with the bulk pile.

The beneficial effects of the utility model:

(1) The column hammer rams the construction waste (i.e. waste filling) and squeezes the surrounding soil to obtain effective compaction and reinforcement. The scope of action includes the depth below the pile tip is 3-5m and the diameter is 2-3m About 10m ³ of the soil mass (the figure shows the soil mass affected by compaction) forms an enlarged head composite carrier consisting of dry hard concrete, construction waste filler and compacted soil mass.

(2) The carrier core multi-component composite pile uses the outer core of loose material to drain water, protect the wall and compact the soil between the piles, while the use of the core pile with high stiffness and strength can effectively improve the bearing capacity of the single pile.

(3) The combination of multi-element composite piles can form a multi-element composite foundation. A variety of media are coordinated and matched, rigid and flexible, mutually reinforcing and improving together, integrating drainage, consolidation, displacement, compaction displacement and vertical reinforcement into one. Multi-component composite piles can be combined with multi-type unit piles to adapt to different soil distribution conditions on site and meet the diversified requirements of the upper structure for bearing capacity.

Compared with other similar soft foundation treatment processes, multi-element composite piles integrate the advantages of multi-type unit piles. Among them, the flexible short pile can accelerate drainage and consolidation, while the carrier and core pile can increase the bearing capacity, and the post-construction settlement of the foundation can be controlled within the range of 2-5cm at most. Compared with rigid piles of the same volume, the bearing capacity of a single pile is equivalent to it, but the cost is about 1/2 (using construction waste or recycled materials).

The multi-component composite pile can also make full use of construction waste as filler, which has multiple functions such as consuming a large amount of construction waste, expanding the source of building materials, reducing the consumption of natural building materials and land area occupation, and can save the cost of building materials and protect the ecological environment. Economic, environmental and social benefits.

Description of drawings

Fig. 1 is a schematic diagram of the front view structure of a bulk pile.

Fig. 2 is a schematic diagram of the front structure of the rammed and expanded carrier-cored composite pile.

Fig. 3 is a schematic diagram of the front view structure of the composite pile with strong core.

Fig. 4 is a schematic diagram of the construction process of the rammed and expanded carrier-core composite pile.

Detailed ways

The carrier-core multi-component composite pile shown in the figure includes a bulk pile 1 that uses construction waste as a material source.

The utility model sets a rigid core pile 2 (that is, the core, usually made of reinforced concrete) in the above-mentioned loose pile, and the rigid core pile is vertically interspersed in the aforementioned loose pile (the core pile and the loose pile The axis coincides), the core pile is flush with the bottom of the bulk pile; the core pile and the bottom of the bulk pile form a spherical carrier expansion head. The expansion head of the carrier is composed of the construction waste packing layer 4 covered by the outer compacted soil layer 5 and the dry hard concrete layer inside the construction waste packing layer 3 .

A construction method for reinforcing soft soil foundations with carrier-core multi-component composite piles. According to different geological conditions, several loose piles, rammed and expanded carrier-core composite piles or/and composite core piles are driven into the soft soil foundation at a certain distance from each other. piles (the number, distribution and distance between loose piles, rammed and expanded carrier-cored composite piles, and reinforced-cored composite piles are determined according to different geological conditions); And the construction steps of the core composite pile are as follows:

1. Recycling of construction waste

In old city reconstruction and demolition sites, construction waste (such as broken bricks, broken tiles, and concrete) is regenerated on-site to obtain the main raw materials for piles, including coarse aggregate and fine-grained soil at all levels; The technical links of separation, crushing, screening, etc. are used to pretreat construction waste to obtain recycled materials of different particle sizes at all levels.

Then, according to the material characteristics of different structural parts of the core pile composite foundation, construction waste is used as the filling material for the ramming carrier; it can not only solve the shortage of natural aggregates, but also solve the problems of construction waste stacking, land occupation and pollution.

2. Construction of bulk piles (i.e. flexible piles)

In order to effectively reduce the post-construction settlement of the soft foundation and accelerate the drainage and consolidation process, the vibrating tube sinking method is used to drive loose piles into the soft soil foundation first, and the pile body materials are replaced by traditional sand and gravel with recycled materials.

(1) The pile driver is in place: close the pile tips and flaps, make the pile tube vertical, and the pile tips are aligned with the pile position marks.

(2) Vibrating sinking tube: Use the weight of the hammer and the weight of the sinking tube to slowly statically press to a certain depth, then turn on the vibrating hammer to vibrate and sink the pile tube to the design depth. Usually during this process, the vibration is kept for 30s for every 0.5m subsidence.

(3) Slightly lift the pile tube to completely open the pile tip flap.

(4) Adding aggregates: After stopping the vibrating sinking tube, immediately put the recycled aggregate of construction waste into the pile tube from the feeding port, and the filling amount is calculated according to the value of the theoretical scheme of the pile body and the filling coefficient.

(5) Vibration extubation: Vibrate for 1 min before extubation, and then extubate while vibrating. For every 0.5-1.0m lift, the catheter was inserted 40cm backwards, and the vibration was left for 30-60s. Repeat this until the whole cannula is pulled out, and the average speed of extubation is 1.2-1.5m/min.

(6) Reverse insertion and compaction: According to the amount of recycled aggregate designed for the single pile, determine the pile length of the first feeding, and perform several reverse insertions until the recycled aggregate in the pile tube is dense.

(7) Second feeding: When the pile tube is lifted to a certain height, stop the vibration and open the second feeding port, and carry out the second feeding until the pile tube is filled.

(8) Pulling out the ground surface: Continue to vibrate while pulling out the pipe until the ground is pulled out; lift the pile pipe above the ground, stop the vibration, and feed the orifice (the third feeding) until the aggregate is filled to the level with the ground surface until flat.

(9) Orifice feeding: start the reverse insertion, and carry out the orifice feeding in time until the design dosage is completely used up.

(10) The hole is pressurized until the front frame is lifted, and the construction of a loose pile is completed.

3. Construction of strong core composite pile

For some loose piles that require compound treatment (interpenetrating rigid core piles), the inner tube is preset during the setting of the vibrating sinking tube (the diameter of the inner tube is approximately equal to the diameter of the core pile, which is about 100-150mm smaller than the diameter of the outer tube) . After the vibratory sinking tube is completed, concrete is poured into the inner tube (to form a rigid core pile), and recycled aggregate is placed in the cavity of the inner and outer tubes, and finally the tube is pulled out while vibrating until the pile body is completed (the bottom of the rigid core pile is lower than the loose core pile). 1m above the bottom of the pile). Among them, the construction process of bulk piles is carried out according to the above-mentioned relevant steps, while the construction process of rigid core piles is described in detail as follows:

(1) Hanging the reinforcement cage. Punch a deep hole with a certain diameter (preferably 150mm) through the inner pipe with a column hammer to provide conditions for good bonding between the subsequent pile body and the carrier. Clean up the floating soil at the bottom of the hole, and then hang the steel cage into the inner pipe, and the bottom is required to sit in the bottom of the deep hole;

(2) Pouring concrete. After the reinforcement cage is placed, pour concrete labeled C25 into the inner pipe to about 50cm above the design pile top elevation. When vibrating the concrete, insert it quickly and pull it out slowly; insert it to the bottom of the pile once and pull it up gradually, and the vibration time is not less than 1.5min.

(3) Pull out the inner (outer) tube. After the concrete is poured, the diesel hammer is pressed on the concrete in the pipe, and then the inner and outer pipes are gradually pulled out. The construction process of vibrating pipe pulling is carried out by referring to the relevant steps in the construction of bulk piles. For the inner pipe, it is compacted while pulling out the pipe to form a carrier-core composite pile. The extubation speed should be controlled at 1m/min to 2m/min.

4. Rammed and expanded carrier core composite pile

For some bulk piles that require composite treatment, the inner tube is preset during the setting of the vibrating immersed tube. Requirements: The diameter of the inner tube is approximately equal to the diameter of the core pile, which is about 100-150mm smaller than the diameter of the outer tube. After the vibrating immersed tube is completed, first carry out tamping and expansion carrier construction, then pour concrete into the inner tube at the same time and put recycled aggregate in the cavity of the inner and outer tubes, and finally vibrate while pulling the tube until the pile body is completed.

The construction process of the tamping carrier is described in detail as follows:

(1) The tamping and expanding pile machine is in place

After checking that the pile driver equipment is normal, the tamping and expanding pile driver can be put in place. Assemble the pile driver and its tamping components on site, and level the pile driver with square logs. A hanging hammer is hung on the main machine to measure and control the verticality of the drill pipe, and at the same time ensure that the column hammer coincides with the center line of the pile hole.

(2) Ramming construction waste

Firstly, raise the column hammer to a certain height to ensure the filling is put in smoothly (step a in Figure 4); secondly, fill a certain amount (0.3-0.5m ³ in total) of construction waste in batches at the bottom of the casing ; Finally, layered hammer compaction (as shown in step b of Figure 4).

The hammering of the column hammer can make the filler squeeze to the surrounding soil, so as to obtain effective compaction and reinforcement effects. The effective range of influence includes: the soil body with a depth of about 3-5m and a diameter of about 2-3m (total volume about 10m ³ ) below the pile tip.

(3) Determination of three-stroke penetration

After the filler is tamped and no longer filled, measure the three-stroke penetration, that is, use a 35kN weight to perform free fall movement with a drop distance of 6m, and tamp three times to measure the penetration.

The three-stroke penetration should be less than 10cm or design requirements. Otherwise, the construction steps of packing and heavy hammer tamping should be repeated until the three-strike penetration meets the design requirements.

(4) Ramping and filling dry hard concrete (step c as shown in Figure 4)

Through the feeding hole of the casing, dry hard concrete is put into the bottom of the hole in stages, and the dry hard concrete is hammered once for every 0.01m ³ filled, and the construction of the tamping and expanding carrier is completed when the accumulative filling is about 0.3m ³ . When the tamping is completed, the bottom of the control hammer is 3-5cm higher than the bottom of the inner pipe.

The dry hard concrete has the same label as the pile body concrete, and at the same time requires: ①Water-cement ratio 0.3-0.4; ②Viber consistency 16-20s. The sand, stone and cement used are kept variable according to the ratio, and the water consumption is mainly controlled, so that the finished product can achieve the effect of clumping in hands and blooming on the ground.

Then pour concrete into the inner pipe (refer to step 3), and pull out the inner (outer) pipe after completion.

The above-mentioned bulk piles, core composite piles, and reinforced core composite piles with rammed and expanded carriers can be installed with connecting steel bars and pile caps as required; specifically, when the bottom elevation of the pile cap connecting steel bars is reached, the pile cap connecting steel bars are placed first, and the pile body is concreted. When the strength reaches 80% of the design value, the pile cap reinforcement is bound and the pile cap concrete is poured.

Finally, the inspection and acceptance of the finished pile; the quality inspection test of the above-mentioned loose piles and composite piles can be carried out 7 to 28 days after the pile is completed, including excavation inspection, drilling inspection and load test. The number of detection piles in each site shall not be less than 0.5% to 1.0% of the total number, and shall not be less than 3 points. In order to ensure the quality of the project, the inspection frequency can be appropriately increased.

In order to shorten the detection time and speed up the operation cycle, the sound wave transmission method is used for rapid detection, and the auxiliary drilling and coring method is used for comparison and correction, which can not only meet the requirements of relatively large frequency detection, but also ensure the accuracy of the detection results.

The features of the above schemes are:

1. The flexible pile is used as the main unit to accelerate the drainage and consolidation of the soft foundation, and the core pile formed after the combination of the flexible pile (tamping and expansion carrier) is used as the main unit to improve the bearing capacity. Various types of pile units work together with the soft soil The action constitutes the multi-element composite foundation. The composite types of flexible piles include two types: ① composite pile with strong core and ② composite pile with reinforced core with rammed and expanded carrier. The selection of composite types and the distribution of pile units can be determined according to the requirements of the bearing capacity of the site.

(1) Ramping expansion (waste) carrier expansion head. Pillar hammers are used to tamp the recycled construction waste filling to squeeze the surrounding soil, thereby achieving effective compaction and reinforcement. The scope of action includes: the soil body with a depth of 3-5m below the pile tip and a diameter of 2-3m about 10m ³ forms a composite carrier of an enlarged head composed of dry hard concrete, waste filler and compacted soil.

(2) Combination of long-short or rigid-flexible piles. Flexible piles (such as sand and gravel piles) usually break through the soft bottom to form short piles. "Short and dense" flexible piles can accelerate drainage and consolidation and vibrate and compact soft soil. In the center of some flexible piles, a rigid core pile (such as a concrete pile) is driven into a harder bearing layer to form a long pile. The long core piles, part of the flexible short piles and the sand and gravel cushion form a multi-component pile composite foundation. Long core piles use loose materials for drainage, wall protection and compaction of the soil between piles, while strong cores with high rigidity and strength can effectively increase the bearing capacity of single piles.

(3) The pile-soil interaction bears the load together. In the multi-component composite foundation, multiple units such as the rammed and expanded carrier, the long core pile, the flexible short pile, and the soil between the piles are coordinated and matched, rigid and flexible, mutually reinforced, and jointly improved, integrating replacement, vertical reinforcement, drainage, and consolidation. , vibration density and filling functions in one. This type of multi-component composite foundation greatly improves the strength and stability of the soft soil foundation, reduces the compressibility, can adapt to the actual working conditions of different soil distributions on site, and can meet the diversified requirements of the upper structure for the bearing capacity.

Claims (3)

1. A multi-component composite pile with a rammed and expanded carrier core, comprising a loose pile (1) vertically fixed in the soil layer and using construction waste as recycled aggregate; it is characterized in that a A rigid core pile (2) formed of reinforced concrete; the bottom end of the rigid core pile is flush with the bottom end of the bulk pile, and the bottom ends of the rigid core pile and the bulk pile are also jointly connected with a spherical carrier expanding head to form Rammed expanded carrier strength core composite pile. 2. The multi-element composite pile with rammed and expanded carrier strength core according to claim 1, characterized in that: the spherical carrier enlarged head is covered by a construction waste filler layer (4) and an outer compacted soil layer (5) and It consists of a dry hard concrete layer (3) inside the construction waste filling layer. 3. The multi-element composite pile with rammed and expanded carrier core core according to claim 2, characterized in that: the axis of the rigid core pile coincides with that of the bulk pile.