CN107806099A - A kind of rigid pile composite foundation stake top filling system and its construction method - Google Patents

Abstract

The invention discloses a rigid pile composite foundation pile top grouting system, which relates to the technical field of foundation treatment, and includes a grouting tube and a grouting tube. There is more than one grouting tube, and the grouting tube corresponds to the rigid pile one by one. Each grouting tube is buried on the pile top foundation of the corresponding rigid pile, and the lower end of each grouting tube covers the pile top of the corresponding rigid pile. The grouting tube communicates with each grouting tube, and each grouting tube The top surface is provided with a cover plate, and the rigid pile composite foundation pile top grouting system also includes a grout discharge pipe, and the grout discharge pipe is connected to each grouting cylinder in series. The invention also discloses a construction method of a rigid pile composite foundation pile top grouting system. The rigid pile composite foundation pile top grouting system is used to improve the reliability and grouting efficiency of the system.

Description

A rigid pile composite foundation pile top grouting system and its construction method

technical field

The invention relates to the technical field of foundation treatment, in particular to a rigid pile composite foundation pile top grouting system and a construction method thereof.

Background technique

At present, the rigid pile composite foundation needs to arrange a cushion layer between the pile top and the foundation, so that the rigid pile can penetrate the cushion layer. The function of the cushion layer is mainly to adjust the load sharing of piles and soil, reduce the stress concentration on the bottom surface of the foundation, and ensure that the piles and soil jointly bear the upper load. However, the thickness, density, and particle gradation of the cushion layer all affect the penetration of rigid piles. When the penetration of rigid piles is too small, the pressure on the top of the pile will be too high, and the top of the pile will be easily damaged. The bearing capacity is often not fully developed; when the penetration of the rigid pile is too large, the load shared by the rigid pile will be too small, the bearing capacity of the pile cannot be fully utilized, and the soil between the piles is prone to local deformation due to the large load. or overall shear failure. Due to the many factors affecting the cushion layer, it is difficult to coordinate the load sharing of piles and soil accurately, and it is easy to cause the rigid piles or the soil between piles to not fully exert their bearing capacity, or to be damaged due to excessive force. In particular, when the soil between piles is provided with a drainage system (vertical drainage body and horizontal drainage body) and needs to be drained and consolidated, the load-bearing effect of rigid piles often limits the vertical compression deformation of the soil between piles, resulting in Insufficient drainage and consolidation will increase the consolidation time.

Post-grouting combined capped rigid pile and drainage body foundation treatment method (patent number 201310067750.6) uses a series grouting bag system on the top of the pile. This grouting system requires the entire pipeline to be sealed, and leakage will occur anywhere and at any time. Causes the grouting to fail, the reliability of the system is low. Controllable rigid pile + drainage body + reinforced cushion composite foundation (patent number 201510798115.4) pile top grouting system, this grouting system focuses on grouting each grouting cylinder separately, without forming a grouting circuit, The grouting efficiency is not very high.

Contents of the invention

One of the objectives of the present invention is to provide a rigid pile composite foundation pile top grouting system to improve the reliability and grouting efficiency of the system.

To achieve the above object, the present invention adopts the following technical solutions:

A pile top grouting system for a rigid pile composite foundation, including a grouting tube and a grouting tube, more than one grouting tube is provided, and the grouting tube corresponds to the rigid pile one by one, and each grouting tube is buried in a corresponding On the pile top foundation of the rigid pile, the lower end of each grouting tube covers the pile top of the corresponding rigid pile. The rigid pile composite foundation pile top grouting system also includes a grout discharge pipe, and the grout discharge pipe is connected to each grouting cylinder in series. Rigid piles are CFG piles, pipe piles or concrete piles.

Preferably, the grout discharge pipe communicates with the upper interior of the previous grouting cylinder, and communicates with the lower interior of the subsequent grouting cylinder.

As a preference, each grouting tube is provided with a first steel flower tube under the interior of the grouting tube, the first tempered tube communicates with the inside of the grouting tube, and the grouting tube runs through the upper end side wall of the previous grouting tube and connects The upper side is connected, and the grout discharge pipe runs through the lower end side wall of the latter grouting cylinder to connect with the first steel flower pipe, and the gap between the grout discharge pipe and each grouting cylinder is sealed.

Preferably, the slurry discharge pipe is located in a mattress layer on the composite foundation.

Preferably, the slurry discharge pipe is steel pipe, PP-R water supply pipe or PVC-U water supply pipe.

As a preference, the top of each grouting cylinder is provided with steel bars with hooks, and the cover plate is provided with reserved holes corresponding to the steel bars with hooks, and embedded steel bars are arranged in the reserved holes, and the cover plates are installed on the corresponding After the grouting cylinder, the steel bars with hooks pass through the reserved holes to buckle the pre-embedded steel bars.

As a preference, the top of each grouting cylinder is provided with a V-shaped groove, and the end of the steel bar with a hook that is far away from the hook is embedded in the wall of the grouting cylinder, and the V-shaped groove is filled with a sealant for sealing the cover plate and the grouting cylinder. Gap between layers of cement mortar. After adopting the above structure, the contact area between the cement mortar and the cover plate is increased, and the tight connection between the grouting cylinder and the cover plate is ensured.

Preferably, the grouting pipe includes a grouting main pipe and a grouting branch pipe, the grouting main pipe includes an outer pipe and an inner pipe, the inner pipe is located inside the outer pipe, and the inner diameter of the outer pipe is greater than the outer diameter of the inner pipe , the grouting branch pipe is provided with more than one, the grouting branch pipe corresponds to the grouting cylinder one by one, and the second steel flower pipe is arranged under each grouting cylinder, the second steel flower pipe communicates with the inside of the grouting cylinder, and each grouting pipe The grouting branch pipe is connected with the second steel flower pipe of the corresponding grouting cylinder, and each grouting branch pipe communicates with the outer pipe.

Preferably, the inner diameter of each grouting tube is 100mm-200mm larger than the diameter of the corresponding rigid pile, and the length of the pile top inserted into the corresponding rigid pile by the lower end of each grouting tube is greater than the pile diameter length of the corresponding rigid pile.

Another object of the present invention is to provide a construction method of a pile top grouting system for a rigid pile composite foundation.

A construction method of a rigid pile composite foundation pile top grouting system, comprising the following steps:

1) Carry out rigid pile construction according to design requirements;

2) After the construction of the rigid pile is completed, remove the foundation soil around the pile top, bury the grouting tube, and the lower end of the grouting tube covers the pile top;

3) The grouting pipe is connected to each grouting cylinder, the inlet of the grouting pipe is outside the scope of the composite foundation, and the grouting pipe is connected to the grouting machine;

4) The grout discharge pipe is connected to each grouting cylinder in series, and the outlet of the grout discharge pipe is outside the scope of the composite foundation;

5) Lay sand or gravel layer by layer around the grouting cylinder, and tamp it until it is flush with the top surface of the grouting cylinder;

6) Install the cover plate tightly on the top surface of the grouting cylinder;

7) Under the action of the upper load, the rigid pile penetrates into the grouting cylinder, and the soil between the piles alone bears the load. When the stress or consolidation degree of the soil between the piles meets the design requirements, the grouting operation is performed. After the strength is reached, the rigid piles play a bearing role, and the composite foundation reaches the joint bearing state of rigid piles and soil.

The beneficial effects of the present invention are:

1. The pile top grouting system of the rigid pile composite foundation of the present invention is provided with a grouting pipe, and the grouting pipe is connected to each grouting cylinder in series, so that the system forms a grouting circuit. When starting grouting, inject grout into the first grouting cylinder through the grouting pipe. When the internal space of the first grouting cylinder is filled, the excess grout will enter the second grouting cylinder through the grouting pipe. When the inner space of the second grouting cylinder is full, the excess grout will enter the third grouting cylinder through the grouting pipe, and so on. Through the continuous flow of grout in the grouting circuit, multiple grouting cylinders can be grouted at one time, which is more efficient than grouting each grouting cylinder separately;

2. The grouting tube is buried in the foundation, and groundwater may seep into the tube. During the grouting process, the grout enters the tube from the first or second steel flower tube at the lower part of the grouting tube, because the specific gravity of the grout is higher than that of water. Large, so that the groundwater is gradually discharged from the grouting pipe on the upper part of the grouting cylinder. Therefore, the grouting pipe not only plays the role of grouting, but also observes the discharge at the outlet of the grouting pipe to determine whether the grouting cylinder is full;

3. If local leakage occurs in the grouting system or there are many grouting cylinders connected in series, resulting in insufficient grouting pressure, and when it is impossible to continuously grout multiple grouting cylinders at one time, you can drag the grouting inner pipe to sequentially grout each grouting cylinder. Supplementary grouting to the grouting cylinder to ensure that each grouting cylinder is fully filled, improving the reliability of the entire grouting system;

4. The rigid pile composite foundation pile top grouting system of the present invention realizes the artificial control of the stress state of the rigid pile and the soil between the piles, so that the foundation load is mainly borne by the soil between the piles in the early stage of the project, which is beneficial to the drainage of the soil between the piles Consolidation and early play of the bearing function, so that the soil between the piles has a good consolidation effect, the bearing capacity is fully exerted, and it is easy to meet the design requirements. The rigid pile will resume the bearing function in the later stage, which can not only share the foundation load, but also reduce the force of the soil between the piles. The settlement deformation of the rigid pile is small, and the post-construction settlement of the foundation can be effectively controlled.

Description of drawings

Fig. 1 is a schematic structural diagram of a pile top grouting system for a rigid pile composite foundation provided by an embodiment of the present invention.

Fig. 2 is a cross-sectional view of a pile top grouting system for a rigid pile composite foundation provided by an embodiment of the present invention.

Fig. 3 is a schematic diagram of the structural arrangement of the grouting pipe in the embodiment of the present invention.

Fig. 4 is a structural schematic diagram of the connection between the grouting pipe and the grouting cylinder in the embodiment of the present invention.

Fig. 5 is a schematic diagram of the structural arrangement of the slurry discharge pipe in the embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a cover plate in an embodiment of the present invention.

Fig. 7 is a perspective view of the grouting cylinder in the embodiment of the present invention.

Reference signs: 1. Soil between piles; 2. Cushion layer; 3. Rigid pile; 4. Vertical drainage body; 5. Grouting cylinder; 6. Cover plate; 7. Grouting pipe; 8. Grouting pipe ;9, V-groove; 10, steel bars with hooks; 11, reserved holes; 12, pre-embedded steel bars; 13, grouting supervisor; 14, outer pipe; , The first steel flower tube; 18 second steel flower tube.

Detailed ways

The technical solution provided by the invention will be described in more detail below in conjunction with FIGS. 1-7 .

As shown in Figure 1, the rigid pile composite foundation includes inter-pile soil 1, cushion layer 2 and rigid pile 3, rigid pile 3 is located inside inter-pile soil 1, mattress layer 2 is located above inter-pile soil 1, inter-pile soil 1 A vertical drainage body 4 is arranged inside, and the top of the vertical drainage body 4 extends into the mattress layer 2 to ensure the interconnection of drainage.

The embodiment of the present invention provides a rigid pile composite foundation pile top grouting system. The rigid pile is a concrete pile. As shown in Figure 1-2, the rigid pile composite foundation pile top grouting system includes a grouting cylinder 5 and a cover plate 6 , Grouting pipe 7 and grouting pipe 8.

The grouting cylinder 5 is a reinforced concrete structure. The number of grouting tubes 5, the number of cover plates 6 and the number of rigid piles 3 are all the same. 5 is buried on the pile top foundation of the corresponding rigid pile 3, the inner diameter of each grouting tube 5 is 150mm larger than the diameter of the corresponding rigid pile 3, and the lower end of each grouting tube 5 covers the pile top of the corresponding rigid pile 3 , the lower end of each grouting tube 5 is inserted into the pile top length of the corresponding rigid pile 3 greater than the pile diameter length of the corresponding rigid pile 3, as shown in Figure 7, the tube top of each grouting tube 5 is provided with a V-shaped Groove 9 and four steel bars 10 with curved hooks, one end of the four steel bars 10 with curved hooks away from the hooks is pre-embedded in the wall of grouting cylinder 5, and the four steel bars 10 with curved hooks are placed in the middle of V-shaped groove 9 Each cover plate 6 is installed on the top surface of the corresponding grouting cylinder 5. As shown in Figure 6, each cover plate 6 is provided with four reserved holes 11 corresponding to the steel bars 10 with hooks. There are pre-embedded steel bars 12 in the reserved holes 11. When each cover plate 6 is installed on the top surface of the corresponding grouting cylinder 5, the steel bars 10 with curved hooks pass through the reserved holes 11 to buckle the pre-embedded steel bars 12, V-shaped grooves 9 is filled with the cement mortar layer of the gap between the sealing cover plate 6 and the grouting cylinder 5 .

As shown in FIGS. 3-4 , the grouting pipe 7 communicates with each grouting cylinder 5 , and the grouting pipe 7 includes a grouting main pipe 13 and a grouting branch pipe 16 . The grouting main pipe 13 includes an outer pipe 14 and an inner pipe 15, the outer pipe 14 is a steel pipe, the inner pipe 15 is a PVC fiber reinforced hose, the inner pipe 15 is located inside the outer pipe 14, and the outer diameter of the inner pipe 15 is smaller than the inner diameter of the outer pipe 14 9mm, the grouting branch pipe 16 is a steel pipe, the number of the grouting branch pipe 16 is the same as the number of the grouting cylinder 5, the grouting branch pipe 16 corresponds to the grouting cylinder 5 one by one, and the second steel flower is provided under each grouting cylinder 5 Pipe 18, the second steel flower pipe 18 communicates with the inside of the grouting tube 5, each grouting branch pipe 16 runs through the side wall below the corresponding grouting tube 5 and is connected with the second steel flower tube 18 of the corresponding grouting tube 5, each injection The gap between the grouting branch pipe 16 and the penetration of the corresponding grouting cylinder 5 side wall is sealed, and each grouting branch pipe 16 communicates with the outer pipe 14 .

As shown in Figure 5, the grout discharge pipe 8 is a steel pipe, and the grout discharge pipe 8 is located in the cushion layer 2 on the composite foundation. Both are equipped with a first steel flower tube 17, the first steel flower tube 17 communicates with the interior of the grouting tube 5, and the grout discharge tube 8 runs through the upper end side wall of the previous grouting tube 5 and communicates with the interior of the grouting tube 5, and the grouting tube 5 is drained. The pipe 8 runs through the lower end side wall of the last grouting cylinder 5 and is connected with the first steel flower pipe 17 of the grouting cylinder 5. The gap between the grouting pipe 8 and the wall of each grouting cylinder 5 is sealed, and the grouting pipe The outlet of 8 is outside the scope of the composite foundation.

Working principle: when grouting starts, inject grout into the first grouting cylinder 5 through the grouting pipe 7, when the internal space of the first grouting cylinder 5 is filled, the excess grout will enter through the grouting pipe 8 The second grouting cylinder 5, when the inner space of the second grouting cylinder 5 is full, the excess grout will enter the third grouting cylinder 5 through the grouting pipe 8, and so on until each grouting cylinder 5 The slurry tank 5 is filled. Under the load of the embankment, the rigid pile 3 penetrates into the grouting cylinder 5, and the soil 1 between the piles alone bears the load. When the stress or consolidation degree of the soil 1 between the piles meets the design requirements, the grouting operation is performed. All construction operations are prohibited within seven days. After the slurry reaches the design strength, the rigid pile 3 will play a bearing role, and the rigid pile composite foundation will reach the joint bearing state of the rigid pile 3 and the soil between the piles 1.

The construction method of the pile top grouting system of the rigid pile composite foundation comprises the following steps: 1) completing the construction of the rigid pile 3, the cushion layer 2 and the vertical drainage body 4; 2) clearing the foundation around the pile top of the rigid pile 3 soil, bury the grouting tube 5, the inner diameter of the grouting tube 5 is 150mm larger than the diameter of the rigid pile 3, and the lower end of the grouting tube 5 covers the pile top of the rigid pile 3, and the insertion length is greater than the length of the diameter of the rigid pile 3; 3) each A grouting branch pipe 16 is connected to the corresponding grouting cylinder 5, and each grouting branch pipe 16 communicates with the outer pipe 14, the inlet of the outer pipe 14 is outside the scope of the composite foundation, and the inlet of the inner pipe 15 is connected with the grouting machine; 4) Grouting The pipe 8 is connected to each grouting cylinder 5 in series according to the grouting sequence. The outlet of the grouting pipe 8 is outside the scope of the composite foundation. After the grouting pipe 8 is installed, check whether the joint between the grouting pipe 7 and the grouting pipe 8 is firm , check whether the connection gap between the grouting tube 5 and the grouting tube 7 and the grouting tube 8 is tight, to ensure that there is no grout leakage during the pressure grouting process; 5) lay gravel in layers around the grouting tube 5, and tamp Dense until the gravel is flush with the top surface of the grouting tube 5; 6) Fill the V-shaped groove 9 of the grouting tube 5 with cement mortar, and install the cover plate 6 tightly on the top surface of the grouting tube 5, and the grouting tube 5 The four steel bars 10 with curved hooks pass through the reserved holes 11 of the cover plate 6 to buckle the pre-embedded steel bars 12 in the reserved holes 11, and then fill the cement mortar into the pre-embedded holes 11; Under the action, the rigid pile 3 penetrates into the grouting cylinder 5, and the soil 1 between the piles alone bears the load. When the stress or consolidation degree of the soil 1 between the piles meets the design requirements, the grouting operation is performed, and the grout reaches the design strength. Finally, the rigid pile 3 plays a bearing role, and the composite foundation reaches the joint bearing state of the rigid pile 3 and the soil 1 between the piles.

Claims (10)

1. A rigid pile composite foundation pile top grouting system, comprising a grouting tube and a grouting tube, the grouting tube is provided with more than one, the grouting tube corresponds to the rigid pile one by one, and each grouting tube is embedded in On the pile top foundation of the corresponding rigid pile, the lower end of each grouting tube covers the pile top of the corresponding rigid pile, the grouting tube communicates with each grouting tube, and the cover plate provided on the top surface of each grouting tube , is characterized in that, the rigid pile composite foundation pile top grouting system also includes a grout discharge pipe, and the grout discharge pipe is connected to each grouting cylinder in series. 2. The pile top grouting system for rigid pile composite foundation according to claim 1, characterized in that, the grout discharge pipe communicates with the upper interior of the previous grouting cylinder, and communicates with the lower interior of the subsequent grouting cylinder. 3. The pile top grouting system for rigid pile composite foundation according to claim 2, characterized in that, each grouting tube is provided with a first steel flower tube under each grouting tube, and the first toughened tube communicates with the inside of the grouting tube. The grout discharge pipe runs through the upper side wall of the previous grouting cylinder and communicates with the interior of the grouting cylinder. The grout discharge pipe penetrates the lower end side wall of the latter grouting cylinder and connects with the first steel flower pipe. The grout discharge pipe The gap between each grouting cylinder is sealed. 4. The pile top grouting system for rigid pile composite foundation according to claim 1, characterized in that, the grout discharge pipe is located in the cushion layer on the composite foundation. 5. The pile top grouting system for rigid pile composite foundation according to claim 1, wherein the grout discharge pipe is a steel pipe, a PP-R water supply pipe or a PVC-U water supply pipe. 6. The pile top grouting system for rigid pile composite foundation according to claim 1, characterized in that, the top of each grouting cylinder is provided with steel bars with hooks, and the cover plate is provided with steel bars with hooks corresponding to There are pre-embedded steel bars in the reserved holes, the cover plate is installed behind the corresponding grouting cylinder, and the steel bars with curved hooks pass through the reserved holes to buckle the pre-embedded steel bars. 7. The pile top grouting system for rigid pile composite foundation according to claim 6, characterized in that, the top of each grouting cylinder is provided with a V-shaped groove, and one end of the steel bar with a hook that is far away from the hook is pre-embedded in the In the wall of the grouting cylinder, the V-shaped groove is filled with a cement mortar layer for sealing the gap between the cover plate and the grouting cylinder. 8. rigid pile composite foundation pile top grouting system according to claim 1, is characterized in that, described grouting pipe comprises grouting main pipe and grouting branch pipe, and described grouting main pipe comprises outer pipe and inner pipe, so The inner pipe is located inside the outer pipe, the inner diameter of the outer pipe is larger than the outer diameter of the inner pipe, and more than one grouting branch pipe is provided, and the grouting branch pipes correspond to the grouting cylinders one by one. There is a second steel flower pipe, the second steel flower pipe communicates with the inside of the grouting cylinder, each grouting branch pipe is connected with the second steel flower pipe of the corresponding grouting cylinder, and each grouting branch pipe communicates with the outer pipe. 9. The rigid pile composite foundation pile top grouting system according to claim 1, wherein the inner diameter of each grouting cylinder is 100mm-200mm larger than the diameter of the corresponding rigid pile, and the lower end of each grouting cylinder is The pile top length of the corresponding rigid pile is greater than the pile diameter length of the corresponding rigid pile. 10. A construction method of a rigid pile composite foundation pile top grouting system as claimed in claim 1-9, characterized in that it comprises the following steps: 1) Carry out rigid pile construction according to design requirements; 2) After the rigid pile construction is completed, remove the foundation soil around the top of the rigid pile, bury the grouting tube, and the lower end of the grouting tube covers the pile top of the rigid pile; 3) The grouting pipe is connected to each grouting cylinder, the inlet of the grouting pipe is outside the scope of the composite foundation, and the grouting pipe is connected to the grouting machine; 4) The grout discharge pipe is connected to each grouting cylinder in series, and the outlet of the grout discharge pipe is outside the scope of the composite foundation; 5) Lay sand or gravel layer by layer around the grouting cylinder, and tamp it until it is flush with the top surface of the grouting cylinder; 6) Install the cover plate tightly on the top surface of the grouting cylinder; 7) Under the action of the upper load, the rigid pile penetrates into the grouting cylinder, and the soil between the piles alone bears the load. When the stress or consolidation degree of the soil between the piles meets the design requirements, the grouting operation is performed. After the strength, the rigid pile plays a bearing role, and the composite foundation reaches the joint bearing state of the rigid pile and the soil between the piles.