阅读说明：本技术 抗拔载体桩的施工方法 (Construction method of uplift carrier pile ) 是由 王继忠 张连喜 徐彤 王光亮 卢俭 于 2021-08-27 设计创作，主要内容包括：本发明提供一种抗拔载体桩的施工方法,将预制管桩和深层载体充分结合以提供较强抗压抗拔能力同时提高整体质量。其步骤包括：1)在预制管桩中心孔内加设通长抗拔锚筋,锚筋下端超出预制管桩一定长度,并视地质条件和设计要求对预制管桩进行封底处理；2)在桩位处将已加设抗拔锚筋的预制管桩沉入至设定深度；3)在中心孔中放置细长重锤；4)在中心孔中填入水泥砂拌合物利用细长重锤进行夯击,重复操作逐渐形成桩端载体并将锚筋包裹嵌固在内；5)通过贯入度或者填料量控制标准之一检测桩端载体的密实度；6)对预制管桩进行灌芯处理。(The invention provides a construction method of a uplift carrier pile, which is characterized in that a precast tubular pile and a deep carrier are fully combined to provide stronger anti-compression and uplift capabilities and improve the overall quality. The method comprises the following steps: 1) adding a through-length anti-pulling anchor bar in a central hole of the precast tubular pile, wherein the lower end of the anchor bar exceeds the precast tubular pile for a certain length, and carrying out bottom sealing treatment on the precast tubular pile according to geological conditions and design requirements; 2) sinking the precast tubular pile added with the anti-pulling anchor bars to a set depth at the pile position; 3) placing an elongated weight in the central bore; 4) filling cement-sand mixtures into the central hole, tamping by using a slender heavy hammer, repeatedly operating to gradually form a pile end carrier and wrapping and embedding the anchor bars; 5) detecting the compactness of the pile end carrier through one of the penetration or filling amount control standards; 6) and (5) performing core filling treatment on the precast tubular pile.)

1. A construction method of a uplift carrier pile is characterized by comprising the following steps:

1) the anti-pulling anchor bars are additionally arranged in the central hole of the precast tubular pile, namely a plurality of anchor bars with the length larger than that of the precast tubular pile are arranged in the central hole of the precast tubular pile at intervals along the inner wall of the central hole, the upper end and the lower end of each anchor bar exceed the two ends of the precast tubular pile by a certain length, the plurality of anchor bars are respectively welded and fixed on the flange plates at the upper end and the lower end of the precast tubular pile, the rigidity of the lower end anchor bar is improved according to geological conditions and design requirements, and the lower end anchor bar and the flange plate at the bottom end of the precast tubular pile can be welded and reinforced by using steel bars;

carry out the back cover processing to precast tubular pile according to geological conditions and design requirement, both utilized back cover steel sheet or precast concrete stake point shutoff precast tubular pile centre bore bottom to prevent that soil or water from entering into in the precast tubular pile centre bore: when the water content in the soil body is higher, a water sealing rubber pad can be additionally arranged between the bottom sealing steel plate or the precast concrete pile tip and the bottom end of the precast tubular pile for further sealing;

2) sinking the precast tubular pile added with the anti-pulling anchor bars to a set depth at the pile position, wherein the sinking mode comprises one or the combination of the following modes:

directly sinking the prefabricated pipe pile into a soil body in a hammering or vibration or static pressure mode;

pre-forming a pile hole in a soil body in a mode of heavy hammer impact or auger drilling or rotary drilling to form a hole, and then putting the prefabricated pipe pile into the pile hole;

thirdly, forming a cement-soil pile with a certain depth and a larger diameter by deep stirring or high-pressure rotary spraying, and then inserting a prefabricated pipe pile into the center of the cement-soil pile;

3) placing a slender heavy hammer with the diameter smaller than that of the central hole in the central hole of the precast tubular pile, if the precast tubular pile is subjected to bottom sealing treatment, lifting the slender heavy hammer for a certain height, and then falling and striking the bottom sealing steel plate or the precast concrete pile tip to separate the bottom sealing steel plate or the precast concrete pile tip from the bottom end of the precast tubular pile;

4) filling a certain amount of cement sand mixtures into a central hole of the precast tubular pile, lifting a slender heavy hammer to a certain height, then dropping to tamp the cement sand mixtures, repeating the filling and tamping operations, gradually forming a carrier with a certain volume and compactness at the lower end of the precast tubular pile, and wrapping and embedding anchor bars at the lower end of the precast tubular pile in the carrier;

5) the compactness of the pile end carrier is detected by one of the following two control standards:

measuring the penetration degree of the long and thin hammer with 3-10 strokes, stopping tamping when the measured value of the penetration degree meets the design value, and continuing to perform the operations of filling the cement-sand mixture and tamping in the step 4) until the measured value of the penetration degree meets the design value when the measured value of the penetration degree does not meet the design value;

secondly, according to geological conditions and load requirements, calculating the set filling amount of the cement sand mixture when the soil mass at the pile end reaches the designed bearing capacity, filling all the cement sand mixture in times according to the set filling amount, and tamping;

6) pouring concrete or cement mortar into the central hole of the precast tubular pile to form a pile; or pouring concrete or cement mortar into the center hole of the precast tubular pile after a reinforcement cage is placed in the center hole of the precast tubular pile to form the pile.

2. The construction method of the uplift carrier pile according to claim 1, wherein in the step 1), the precast tubular pile comprises a prestressed tubular pile, a precast hollow bamboo joint pile and a precast hollow square pile.

3. The construction method of a uplift carrier pile according to claim 1, wherein in the step 1), the length of the lower end of the anchor bar exceeding the lower end of the precast tubular pile is more than 20 cm.

4. The construction method of the uplift carrier pile according to claim 1, wherein in the step 1), the bottom sealing treatment is performed on the precast tubular pile according to geological conditions and design requirements, which means that in some cases, when a pile hole is formed in a soil body in advance and then the precast tubular pile is placed in the pile hole, the bottom sealing treatment is not required on the precast tubular pile.

5. The construction method of the uplift carrier pile according to claim 1, wherein in the step 1), the area of the back cover steel plate is larger than the area of the central hole of the precast tubular pile, the back cover steel plate is fixed with the flange at the bottom end of the precast tubular pile in a bolt or welding manner, and the strength of the bolt or welding fixation is properly reduced, so that the back cover steel plate can be driven away from the bottom end of the precast tubular pile in the subsequent process.

6. The method for constructing a carrier pile according to claim 1, wherein in the step 3), the diameter of the slender weight is smaller than the diameter of the central hole of the precast tubular pile by 2cm or more, and the weight of the slender weight is 1 ton to 15 tons.

7. The method for constructing a carrier pile according to claim 1, wherein in step 3), in order to prevent damage to the bottom of the precast tubular pile caused by the slender hammering of the bottom-sealing steel plate or the precast concrete pile tip, the slender hammer is lifted to a certain height and then falls down to strike the bottom-sealing steel plate or the precast concrete pile tip after a small amount of cement-sand mixture is filled into the central hole of the precast tubular pile.

8. The method for constructing a carrier pile according to claim 1, wherein in the step 3) and the step 4), the cement-sand mixture comprises cement, sand, water, small-particle-size crushed stone, slag and steel slag.

9. The method for constructing a carrier pile according to claim 1, wherein in the step 4), when the operations of filling the cement-sand mixture and tamping are repeated, the amount of the cement-sand mixture is not required to be excessively large, and the number of tamping times after each filling is 1 to 5.

10. The construction method of the carrier pile according to claim 1, wherein in the step 5), a value range of a design value is 0-50 cm.

11. The method of claim 1, wherein in the step 5), the penetration is the value of the current subsidence of the slender weight after the slender weight falls freely to hit the bottom filler at the same height without filling the cement-sand mixture, i.e. the penetration of 1 hit, and the penetration of the next time is not greater than the penetration of the previous time.

12. The construction method of the carrier pile according to claim 1, wherein in the process of the step 4) and the step 5), whether the precast tubular pile floats upwards is observed, the precast tubular pile is re-beaten or re-pressed according to the floating value of the precast tubular pile, a cushion pad is placed at the top end of the precast tubular pile, the precast tubular pile is sunk in a hammering mode, a vibration mode or a static pressure mode, and the sinking value is not more than the floating value of the precast tubular pile; if the precast tubular pile does not float upwards or the floating amount is very small, secondary striking or secondary pressing is not needed.

13. The method for constructing a carrier pile according to claim 1, wherein in the step 6), the concrete is poured into the central hole of the prestressed concrete pipe pile, and the number of the concrete is equal to or smaller than that of the precast pipe pile.

Technical Field

The invention relates to the field of civil engineering, in particular to a construction method of a uplift carrier pile.

Background

Along with the continuous increase of building quantity and the continuous improvement of construction science and technology level, also corresponding the enhancement to the requirement of building pile foundation, the pile foundation not only needs compressive resistance many times, still need provide certain resistance to plucking. For example, in a building site with a high ground water level, an area with strong wind pressure or an area with high earthquake resistance requirement, corresponding anti-floating and anti-pulling measures need to be taken for an underground structure so as to ensure the safety and normal use of a building (structure). Currently, the most commonly used uplift pile structure or anti-floating anchor rod mainly relies on the friction force between the body of the uplift pile and the rock (soil) layer or the anchoring force of the anchor rod to provide the uplift force. Patent No. 98124854.3 discloses a method for constructing a concrete anchor pile, in which an expandable portion of a cage is expanded by tamping a filler with the cage, thereby forming an expanded head at the end of the pile. However, in the implementation, the method has the main problems that the hammer bottom often directly hits on the steel bar of the diameter-expandable part due to the large energy of the used heavy hammer, so that the steel bar is easy to shear and break, and the pulling resistance is lost; secondly, although the inner layer of the steel bar of the diameter-expanding part is filled with the compacted filling material, the outer layer of the steel bar is only an original soil layer, so that the steel bar of the diameter-expanding part is not fully wrapped by the filling material; thirdly, the anti-pulling force is provided by the friction force of the steel bar of the diameter-expanding part and the expanding head, so that the anti-pulling force provided by the method is insufficient and unstable. In addition, in a soil layer with soft geology or rich underground water content, the quality of a cast-in-place concrete pile body is unstable, so that the quality problems of diameter shrinkage, pile breakage and the like are easily caused, and the engineering quality is seriously influenced.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a construction method of a uplift carrier pile, by which an anchor pile having a high uplift resistance can be formed quickly and efficiently, or a concrete pile having both a high compressive bearing capacity and an uplift resistance can be formed.

In order to achieve the above object, the construction method of the uplift carrier pile of the present invention comprises the steps of:

1) the anti-pulling anchor bars are additionally arranged in the central hole of the precast tubular pile, namely a plurality of anchor bars with the length larger than that of the precast tubular pile are arranged in the central hole of the precast tubular pile at intervals along the inner wall of the central hole, the lower ends of the anchor bars exceed the lower end of the precast tubular pile for a certain length, the plurality of anchor bars are welded and fixed on flange plates at the upper end and the lower end of the precast tubular pile respectively, the rigidity of the anchor bars at the lower end is improved according to geological conditions and design requirements, and the anchor bars at the lower end and the flange plate at the bottom end of the precast tubular pile can be welded and reinforced by using steel bars;

carry out the back cover processing to precast tubular pile according to geological conditions and design requirement, both utilized back cover steel sheet or precast concrete stake point shutoff precast tubular pile centre bore bottom to prevent that soil or water from entering into in the precast tubular pile centre bore: when the water content in the soil body is higher, a water sealing rubber pad can be additionally arranged between the bottom sealing steel plate or the precast concrete pile tip and the bottom end of the precast tubular pile for further sealing;

2) sinking the precast tubular pile added with the anti-pulling anchor bars to a set depth at the pile position, wherein the sinking mode comprises one or the combination of the following modes:

directly sinking the prefabricated pipe pile into a soil body in a hammering or vibration or static pressure mode;

pre-forming a pile hole in a soil body in a mode of heavy hammer impact or auger drilling or rotary drilling to form a hole, and then putting the prefabricated pipe pile into the pile hole;

thirdly, forming a cement-soil pile with a certain depth and a larger diameter by deep stirring or high-pressure rotary spraying, and then inserting a prefabricated pipe pile into the center of the cement-soil pile;

3) placing a slender heavy hammer with the diameter smaller than that of the central hole in the central hole of the precast tubular pile, if the precast tubular pile is subjected to bottom sealing treatment, lifting the slender heavy hammer for a certain height, and then falling and striking the bottom sealing steel plate or the precast concrete pile tip to separate the bottom sealing steel plate or the precast concrete pile tip from the bottom end of the precast tubular pile;

4) filling a certain amount of cement sand mixtures into a central hole of the precast tubular pile, lifting a slender heavy hammer to a certain height, then dropping to tamp the cement sand mixtures, repeating the filling and tamping operations, gradually forming a carrier with a certain volume and compactness at the lower end of the precast tubular pile, and wrapping and embedding anchor bars at the lower end of the precast tubular pile in the carrier;

5) the compactness of the pile end carrier is detected by one of the following two control standards:

measuring the penetration degree of the long and thin hammer with 3-10 strokes, stopping tamping when the measured value of the penetration degree meets the design value, and continuing to perform the operations of filling the cement-sand mixture and tamping in the step 4) until the measured value of the penetration degree meets the design value when the measured value of the penetration degree does not meet the design value;

secondly, according to geological conditions and load requirements, calculating the set filling amount of the cement sand mixture when the soil mass at the pile end reaches the designed bearing capacity, filling all the cement sand mixture in times according to the set filling amount, and tamping;

6) pouring concrete or cement mortar into the central hole of the precast tubular pile to form a pile; or pouring concrete or cement mortar into the center hole of the precast tubular pile after a reinforcement cage is placed in the center hole of the precast tubular pile to form the pile.

In the construction method of the uplift carrier pile, preferably, the precast tubular pile in the step 1) includes a prestressed tubular pile, a precast hollow bamboo joint pile and a precast hollow square pile.

In the construction method of the uplift carrier pile, preferably, in the step 1), the length of the lower end of the anchor bar exceeding the lower end of the precast tubular pile is more than 20 cm.

In the construction method of the uplift carrier pile, preferably, in the step 1), the bottom sealing treatment is performed on the precast tubular pile according to geological conditions and design requirements, which means that in some cases, when a pile hole is formed in a soil body in advance and then the precast tubular pile is placed in the pile hole, the bottom sealing treatment is not required on the precast tubular pile.

In the construction method of the uplift carrier pile, preferably, in the step 1), the area of the bottom sealing steel plate is larger than the area of the central hole of the precast tubular pile, the bottom sealing steel plate is fixed with the flange plate at the bottom end of the precast tubular pile in a bolt or welding mode, and the strength of the bolt or welding fixation is properly reduced, so that the bottom sealing steel plate can be favorably impacted away from the bottom end of the precast tubular pile in the subsequent process.

In the construction method of the uplift carrier pile, preferably, in the step 3), the diameter of the slender weight is smaller than the diameter of the central hole of the precast tubular pile by more than 2cm, and the weight of the slender weight is 1 ton to 15 tons.

In the construction method of the uplift carrier pile, preferably, in the step 3), in order to prevent the damage to the bottom of the precast tubular pile caused by the long and thin hammering of the bottom-sealing steel plate or the precast concrete pile tip, a small amount of cement-sand mixture can be filled into the central hole of the precast tubular pile, and then the long and thin hammer is lifted to a certain height and then falls down to strike the bottom-sealing steel plate or the precast concrete pile tip.

In the construction method of the uplift carrier pile, preferably, in the step 3) and the step 4), the cement-sand mixture is made of cement, sand and water, and also comprises small-particle-size crushed stone, slag and steel slag.

In the construction method of the uplift carrier pile, preferably, in the step 4), when the operations of filling the cement-sand mixture and tamping are repeated, the number of the cement-sand mixture filled each time is not required to be too large, and the tamping frequency after each filling is 1-5 times.

In the construction method of the uplift carrier pile, preferably, in the step 5), a value range of the design value is 0-50 cm.

In the above construction method of the uplift carrier pile, preferably, in the step 5), the penetration is a current sinking value after the slender heavy hammer freely falls and hits the bottom filler at the same height without filling cement-sand mixture, that is, the penetration of 1 hit, and the penetration of the next time is not greater than the penetration of the previous time;

in the construction method of the uplift carrier pile, preferably, in the processes of the step 4) and the step 5), whether the precast tubular pile floats upwards is observed, the precast tubular pile is re-beaten or re-pressed according to the floating value of the precast tubular pile, a cushion pad is placed at the top end of the precast tubular pile, the precast tubular pile is sunk in a hammering or vibration or static pressure mode, and the sinking value is not more than the floating value of the precast tubular pile; if the precast tubular pile does not float upwards or the floating amount is very small, secondary striking or secondary pressing is not needed.

In the above construction method of the uplift carrier pile, preferably, in the step 6), the concrete poured into the central hole of the prestressed concrete pipe pile has a label equal to or less than that of the precast pipe pile.

According to the construction method of the uplift carrier pile, the precast tubular pile and the deep carrier are combined, the respective advantages of the precast tubular pile and the deep carrier are fully exerted, and the pressure-resistant uplift capacity and the overall quality of the whole pile are remarkably improved. Through add in precast tubular pile centre bore and establish logical long anchor bar, pack the bottom of anchor bar in the deep carrier of pile tip through abundant packing tamp parcel again, like this when the pile body is pulled out, its resistance to plucking power just comprises the triplex: firstly, the anchor bars are embedded in the pile end carriers to form a gripping force, the height of the pile end carriers is generally 3-5 m according to the change of soil layers and fillers, the width of the pile end carriers is generally 2-3 m, and the uplift resistance provided by the pile end carriers with large volume in a deeper soil layer is very strong; secondly, the weight of the precast tubular pile is reduced; thirdly, the frictional resistance between the precast tubular pile and the peripheral soil body. Compared with other pile types which only can provide one or two pull-out resistance modes, the invention fully combines the three pull-out resistance modes into a whole and has stronger pull-out resistance. Meanwhile, the pile end carrier adopts the cement mixture as the filler, the density and the strength of the hardened cement mixture are obviously higher than those of the common compacted filler, the hardening combination with the pile body concrete material is more facilitated, and the pile body quality and the uplift resistance are further enhanced; in addition, the prefabricated tubular pile is used as the pile body, so that the influence of the soil layer of the pile body on the quality of the pile body is not required to be considered completely. Meanwhile, the anti-pulling carrier pile is not limited to single anti-pulling, has the same or even higher anti-pulling capacity, can form two types of pure anti-pulling anchor piles and anti-pulling carrier piles, and can fully exert technical advantages in geological and environment complex areas or higher building applications.

Drawings

FIG. 1 is a schematic illustration of a process for forming a uplift carrier pile according to one embodiment of the invention; fig. 2 is a schematic view of the precast tubular pile with the anchor bars and the back cover steel plate in the embodiment.

Detailed Description

The invention is further illustrated by the following specific examples.

Fig. 1 is a schematic view of a process of a uplift carrier pile according to an embodiment of the present invention, first, as shown in fig. 1 (1), 6 anchor bars 3 having a length greater than that of a precast tubular pile 1 are arranged at intervals along an inner wall of a central hole in a central hole of the precast tubular pile 1, a lower end of each anchor bar 3 exceeds a lower end of the precast tubular pile 1 by 60cm, an upper end of each anchor bar 3 is flush with an upper end of the precast tubular pile 1, the anchor bars 3 are welded and fixed at flanges 2 at upper and lower ends of the precast tubular pile 1, a lower end of each anchor bar 3 is welded with a flange 2 by using a steel bar 4, and a stress strength of each anchor bar 3 is reinforced; meanwhile, the bottom end of the central hole of the precast tubular pile 1 is blocked by a bottom sealing steel plate 5, so that soil or water is prevented from entering the central hole of the precast tubular pile 1, the area of the bottom sealing steel plate 5 is larger than that of the central hole of the precast tubular pile 1, and the bottom sealing steel plate is fixed with a flange 2 at the bottom end of the precast tubular pile 1 in a welding manner; then, as shown in (2) in fig. 1, sinking the precast tubular pile 1 with the anti-pulling anchor bars 3 and the bottom-sealing steel plates 5 added at the pile position into the soil body in a hammering manner; then, as shown in (3) in fig. 1, sinking the precast tubular pile 1 to a set depth by continuous hammering; then, as shown in (4) in fig. 1, placing a slender weight 6 suspended by a steel wire rope 7 in the central hole of the precast tubular pile 1, wherein the diameter of the slender weight 6 is smaller than that of the central hole of the precast tubular pile 1, filling a certain amount of cement sand mixture 8 into the central hole of the precast tubular pile 1, lifting the slender weight 6 for a certain height, then performing falling tamping, so that the bottom-sealed steel plate 5 is separated from the bottom end of the precast tubular pile 1, and then performing operation of filling the cement sand mixture 8 and lifting the slender weight 6 for falling tamping; then, as shown in (5) in fig. 1, repeatedly performing operations of filling cement sand mixture 8, lifting slender heavy hammer 6, then dropping and tamping, gradually forming carrier 9 with certain volume and compactness at the lower end of the precast tubular pile, and wrapping and embedding anchor bars 3 at the lower end of the precast tubular pile 1 in the carrier 9; then, as shown in (6) in fig. 1, the penetration of the long and thin hammer idle blow 3 is measured, when the measured value of the penetration of the 3 blows is less than the designed value of 15 cm and the penetration of the next blow is not more than the penetration of the previous blow, the tamping is stopped, and the long and thin hammer 6 is lifted; finally, as shown in (7) in fig. 1, pouring concrete 10 into the central hole of the precast tubular pile 1 to the top end of the tubular pile, and completing the construction of the uplift-resistant carrier pile.

Fig. 2 is a schematic diagram of the precast tubular pile additionally provided with anchor bars and a bottom-sealing steel plate in the embodiment of fig. 1, as shown in fig. 2, the anchor bars 3 with the length greater than that of the precast tubular pile 1 are arranged in the central hole of the precast tubular pile 1 at intervals along the inner wall of the central hole, the lower ends of the anchor bars 3 exceed the lower end of the precast tubular pile 1 by 60cm, the upper ends of the anchor bars 3 are flush with the upper end of the precast tubular pile 1, the anchor bars 3 are welded and fixed at the flanges 2 at the upper and lower ends of the precast tubular pile 1, the lower ends of the anchor bars 3 are welded with the flanges 2 by using the reinforcing steel bars 4, and the stress strength of the anchor bars 3 is reinforced; meanwhile, the bottom end of the central hole of the precast tubular pile 1 is sealed by the bottom sealing steel plate 5, the area of the bottom sealing steel plate 5 is larger than that of the central hole of the precast tubular pile 1, and the bottom sealing steel plate is fixed with the flange 2 at the bottom end of the precast tubular pile 1 in a welding mode.