Construction method of solidified soil pile composite foundation

Abstract

The invention provides a construction method of a solidified soil pile composite foundation, solidified soil piles formed by premixed solidified soil materials are used as reinforcing pile bodies in the composite foundation, and the construction of the solidified soil piles is carried out in a form of taking groups as units, and comprises the following steps: 1) selecting the number of the solidified soil piles in the area of the group according to pile position arrangement and field conditions; (2) the pile casings with the same number are sunk into all pile positions of the pile group through a soil discharging method or a soil taking method to form pile holes, and all the pile holes of the pile group are isolated and protected through the pile casings; (3) the taken-out soil body or other soil bodies are used as main materials, and premixed solidified soil is manufactured through a ground machine; (4) pouring the prepared premixed solidified soil into all pile holes of the group of piles respectively, and (5) upwards lifting all pile casings of the group of piles out of the earth surface, so that all pile holes are filled with the premixed solidified soil, and construction of the group of solidified soil piles is completed.

Description

Technical Field

[0001] The invention relates to a foundation, and in particular to a construction method of a solidified soil pile composite foundation. Background Art

[0002] Cement soil mixing pile is a reinforcement method used in soft soil foundation. It uses cement as a curing agent. The soft soil and curing agent are forcibly mixed deep in the foundation soil through a mixing machine. The physical and chemical reaction between the curing agent and the soft soil is used to harden the soft soil into a foundation with integrity, water stability and a certain strength. The conventional construction methods include powder spraying, high-pressure rotary spraying and deep mixing. However, the problems with these methods are that, first, due to the changes in the hardness and depth of the soil layer in the foundation, the diameter and strength of the mixing pile change, and the difference between piles is greater, especially the uniformity of mixing or curing of the deeper soil cannot be guaranteed, so the strength and stability of the composite foundation formed are relatively low; second, the construction process only improves the strength of the cement pile itself, but does not have a positive effect on the foundation soil around the pile body; third, it is easy to cause slurry leakage during the mixing process, and the slurry often needs to be transported out, causing waste and polluting the environment.

[0003] In addition, in various treatment methods of composite foundation, the pile position design is based on Figure 1 The sequence of construction of the root pile next to another pile is very slow. When the soil is squeezed, the soil in and around the pile hole will be squeezed outward. If the piles are still constructed in the order of adjacent piles, it is easy to affect or even damage the adjacent piles, reduce the bearing capacity of single piles and pile groups, and cause quality problems. In addition, the hardening process of the cement soil pile is relatively slow. If the protection of the adjacent piles is not paid attention to, it is also very easy to have a negative impact on the quality of the pile body. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to propose a construction method of a solidified soil pile composite foundation, which adopts premixed solidified soil as the material to form a reinforced pile body in the composite foundation, thereby solving the problems of insufficient uniformity of deep mixing and low strength of cement soil piles. At the same time, it pays attention to the isolation and protection of adjacent piles during construction, overcoming the defect of mutual influence between adjacent piles in traditional processes, thereby improving the bearing capacity of single piles and pile groups in the composite foundation, and achieving the technical effect of saving and environmental protection.

[0005] To achieve the above-mentioned object, in the construction method of the composite foundation of the solidified soil pile provided by the present invention, the solidified soil pile is formed by using the premixed solidified soil material as the reinforced pile body in the composite foundation, and the construction of the solidified soil pile is carried out in the form of a group as a unit, and the specific steps are as follows: 1) According to the pile position layout and site conditions, select the number of solidified soil piles in this group area; 2) At all pile positions of this group of piles, the same number of casings are sunk by soil removal or soil excavation to form pile holes, so that all pile holes of this group of piles are isolated and protected by casings: 3) Using the extracted soil or other soil as the main material, make premixed solidified soil through ground machinery; 4) Pour the prepared premixed solidified soil into all the pile holes of this group of piles; 5) Lift all the casings of this group of piles upwards to the surface, so that the premixed solidified soil fills all the pile holes, thus completing the construction of this group of solidified soil piles.

[0006] The characteristics and advantages of making premixed solidified soil by ground machinery are that the production process is visible and controllable, and the proportion can be adjusted at any time according to different needs to obtain solidified soil materials with different strengths or slumps, and then the solidified soil materials are poured back into the pile holes to form solidified soil piles. Compared with the method of directly mixing conventional cement soil piles in deep soil, the uniformity and overall strength of the solidified soil piles are significantly improved.

[0007] The characteristics and advantages of constructing multiple solidified soil piles at a time in groups are that during the entire construction process of the pile group, each pile is isolated and protected by a casing and a wall, which can completely avoid the mutual influence between adjacent piles and ensure the integrity of the pile body. It can avoid defects such as shrinkage, expansion, and broken piles in single piles, and at the same time ensure the overall quality of the pile group, so that the quality and strength of the composite foundation formed are higher.

[0008] It is best to construct the next group of solidified soil piles after the construction of the current group of solidified soil piles is completed on the premise that the pile body material of the current group of solidified soil piles has hardened, or the distance from the outside of the current group of piles is at least one pile. The purpose of this requirement is to further avoid the mutual influence between adjacent piles and ensure the integrity of the single pile and pile group.

[0009] Preferably, the number of piles in a group is 3 to 16, and the piles are arranged in multiple rows and multiple columns, or in a single row and multiple columns, or in a single column and multiple rows. In most cases, multiple rows and multiple columns are preferably used, such as 2×3, 3×3, 3×4, which is determined based on the leveling conditions of the site, nearby buildings, the number of construction equipment, and other conditions.

[0010] Preferably, the construction process of the soil removal method described in step 2) above includes: using a casing with a flap bottom seal, using a puller to clamp the casing and vibrate it to a set depth, squeezing and emptying the foundation soil to the outside of the casing to form a pile hole. Using the soil removal method in relatively loose and weak foundation soil can produce a strong compaction and reinforcement effect on the surrounding soil, further improving the strength and bearing capacity of the foundation.

[0011] Preferably, the flap bottom sealing member is arranged at the bottom of the casing, and when the casing is sunk, the flap closes inwards to seal the bottom of the casing, and when the casing is lifted upwards, the flap opens outwards under the influence of gravity or the pressure of the stuffing inside the casing, so that the bottom of the casing is connected. The flap bottom sealing member can complete the operations of sinking and sealing the bottom of the casing and pulling out the material more quickly and efficiently.

[0012] Preferably, the flap bottom sealing member has a flat bottom or a pointed bottom when closed inwardly, which can be selected depending on the hardness or softness of the soil of the foundation.

[0013] Preferably, the construction process of the soil extraction method described in step 2) above includes: using a casing with an opening at the bottom, using a puller to clamp the casing and vibrate it to a set depth, and then taking out all the soil that has flowed into the casing to form a pile hole; or using a casing with an opening at the bottom and an inner sleeve, with soil-blocking barbs provided in the middle and lower part of the inner sleeve, using a puller to clamp the casing and the inner sleeve at the same time and vibrate them synchronously or first sink the casing and then sink the inner sleeve to a set depth, then lift the inner sleeve upward and empty the soil in the inner sleeve to form a pile hole. In this step, the operation of sinking the inner sleeve into the inner cavity of the casing and then lifting the inner sleeve and emptying the soil can be performed at one time or in stages.

[0014] In both the soil discharge method and the soil excavation method, a construction combination of a puller and a casing is used. Compared with the process of using an auger or a rotary drill to extract the foundation soil, this combination can more efficiently and economically empty or extract the foundation soil to form a pile hole with a casing and wall.

[0015] Preferably, the method for making the premixed solidified soil described in step 3) above includes: using soil taken from the site foundation or other soil as the main material, using one or more materials of curing agent, fly ash, sand, gravel, and admixture as auxiliary materials, and uniformly mixing the main material, auxiliary material, and water in a certain proportion through a ground mixing container to form premixed solidified soil, the slump of the premixed solidified soil is 3 to 15 cm, and the strength after hardening is 2 to 6 MPa. Most of the production methods are to first mix powdered curing agents such as cement and fly ash with water to form curing agent slurry, and then mix the curing agent slurry with materials such as soil and sand to form a solidified soil material, wherein the proportion of the main material, auxiliary material, and water can be adjusted in time according to the project requirements.

[0016] In the final stage of construction, after the construction of several groups of solidified soil replacement piles is completed in the entire project site, if there are any remaining scattered single piles or single rows and columns of piles, additional construction is required after the pile materials of the adjacent piles are completely hardened.

[0017] The characteristics and advantages of the present invention also lie in that the foundation soil is directly used as building materials, and the cost is low; and no abandoned soil is generated during the entire construction process, and no waste and pollution of soil is caused, which is economical and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a group of pile process of the premixed solidified soil replacement pile composite foundation construction method of the present invention; Figure 2 It is a schematic diagram of the arrangement of piles in the site and the construction sequence; Figure 1 In the figure, 1 is the valve bottom seal, 2 is the casing, and 3 is the premixed solidified soil. DETAILED DESCRIPTION

[0019] The present invention is further described below by means of the accompanying drawings and specific embodiments.

[0020] Figure 1 FIG. 1 is a side view schematic diagram of a process of a group of premixed solidified soil replacement piles in one embodiment of the present invention. First, Figure 1 As shown in a, select 6 piles arranged in a 2×3 arrangement as a group of piles; then, as Figure 1 As shown in FIG. 2 , at the positions of all 6 piles of the group of piles, 6 casings 2 with flap bottom sealing members 1 are sunk to a set depth by using a driving and pulling machine. When the casings 2 are sunk, the flaps of the flap bottom sealing members 1 are closed inward to seal the bottom of the casings 2, forming 6 pile holes with casings 2 as protective walls, so that all the pile holes of the group of piles are isolated and protected by the casings 2. Then, as shown in FIG. Figure 1 As shown in c, using the soil transported from outside as the main material, cement curing agent and fly ash as auxiliary materials, the main material, auxiliary material and water are mixed in a certain proportion in a ground mixing container to form a premixed solidified soil 3, and the slump of the premixed solidified soil 3 is controlled to be 8cm; then, as shown in Figure 1 As shown in FIG. 4 , the prepared premixed solidified soil 3 is poured into all the six casings 2 of the pile group to the surface of the foundation; then, as shown in FIG. Figure 1 As shown in Fig. e, the casing 2 in the pile group is lifted upward by a driving and pulling machine. During the lifting process, the premixed solidified soil 3 poured into the casing 2 exerts pressure on the flap bottom sealing member 1, and the flap of the flap bottom sealing member 1 opens outward, so that the premixed solidified soil 3 flows out from the bottom of the casing 2 and fills the pile hole; finally, as shown in Fig. Figure 1 As shown in FIG. 5 , all six casings 2 are lifted out of the ground surface, completing the construction of the group of six solidified soil piles.

[0021] Figure 2The present invention is a schematic diagram of different grouping arrangements and construction sequences of various pile groups in a site of an embodiment. The construction sequence requires that after the solidified soil replacement pile body material of a certain group of piles is completely hardened, the next group of solidified soil replacement piles shall be constructed at an adjacent position outside the group of piles; or before the solidified soil replacement pile body material of a certain group of piles is completely hardened, when the next group of solidified soil replacement piles are constructed, they must be at least one pile away from the outside of the group of piles; in this embodiment, the entire site is designed as 6 rows × 11 columns with a total of 66 premixed solidified soil replacement piles, Figure 2 In a, a 2-row × 3-column grouping arrangement is adopted, and the construction sequence is to first construct the first group of 6 piles in the 1st and 2nd rows and the 1st, 2nd and 3rd columns, and before the solidified soil replacement pile material of the first group of piles is completely hardened, then the second group of 6 piles in the 1st and 2nd rows and the 5th, 6th and 7th columns are constructed, and then the third group of 6 piles in the 1st and 2nd rows and the 9th, 10th and 11th columns are constructed. In this way, the grouping construction is carried out successively until all 66 premixed solidified soil replacement piles are completed; Figure 2 In b, a 6-row × 1-column grouping arrangement is adopted, and the construction sequence is to first construct the first group of 6 piles in the first column, and then to carry out group construction of the third column, the fifth column, the seventh column, the ninth column, the eleventh column, the second column, the fourth column, the sixth column, the eighth column, and the tenth column.

Claims

1. A construction method for a solidified soil pile composite foundation, wherein: The premixed solidified soil material is used to form solidified soil piles as the reinforced pile body in the composite foundation, and the construction of the solidified soil piles is carried out in the form of groups as units. The specific steps are: 1) According to the pile position layout and site conditions, select the number of solidified soil piles in this group area; 2) At all pile positions of this group of piles, the same number of casings are sunk by soil removal or soil excavation to form pile holes, so that all pile holes of this group of piles are isolated and protected by casings: 3) Using the extracted soil or other soil as the main material, make premixed solidified soil through ground machinery; 4) Pour the prepared premixed solidified soil into all the pile holes of this group of piles; 5) Lift all the casings of this group of piles upwards to the surface, so that the premixed solidified soil fills all the pile holes, thus completing the construction of this group of solidified soil piles.

2. The construction method of the solidified soil pile composite foundation according to claim 1, characterized in that: After the construction of this group of solidified soil piles is completed, the prerequisite for the construction of the next group of solidified soil piles is that the pile body material of this group of solidified soil piles has been hardened, or there is a distance of at least one pile away from the outside of this group of piles.

3. The construction method of the solidified soil pile composite foundation according to claim 1, characterized in that: The number of piles in a group is 3 to 16, and the piles are arranged in multiple rows and multiple columns, or a single row and multiple columns, or a single column and multiple rows.

4. The construction method of the solidified soil pile composite foundation according to claim 1, characterized in that: The construction process of the soil discharge method described in step 2) includes: using a casing with a flap bottom seal, using a puller to clamp the casing and vibrate it to sink it to a set depth, squeezing and emptying the foundation soil to the outside of the casing to form a pile hole.

5. The construction method of the solidified soil pile composite foundation according to claim 4, characterized in that: The above-mentioned valve bottom sealing member is arranged at the bottom of the casing. When the casing sinks, the valve closes inwardly to seal the bottom of the casing. When the casing is lifted upward, the valve opens outwardly under the influence of gravity or the pressure of the filling in the casing to make the bottom of the casing pass through.

6. The construction method of the solidified soil pile composite foundation according to claim 4, characterized in that: The flap bottom sealing member has a flat bottom or a pointed bottom when closed inwardly.

7. The construction method of the solidified soil pile composite foundation according to claim 1, characterized in that: The construction process of the soil extraction method described in step 2) includes: using a casing with an opening at the bottom, using a puller to clamp the casing and vibrate it to a set depth, and then taking out all the soil that has flowed into the casing to form a pile hole; or using a casing with an opening at the bottom and an inner sleeve, the middle and lower part of the inner sleeve is provided with soil-blocking barbs, using a puller to clamp the casing and the inner sleeve at the same time and vibrate them synchronously or first sink the casing and then sink the inner sleeve to a set depth, and then lift the inner sleeve upward and empty the soil in the inner sleeve to form a pile hole.

8. The construction method of the solidified soil pile composite foundation according to claim 1, characterized in that: The method for preparing the premixed solidified soil described in step 3) comprises: using soil taken from the site foundation or other soil as the main material, using one or more materials selected from the group consisting of a curing agent, fly ash, sand, gravel, and admixtures as auxiliary materials, and uniformly mixing the main material, the auxiliary material, and water in a certain proportion in a ground mixing container to form the premixed solidified soil. The slump of the premixed solidified soil is 3 to 15 cm, and the strength after hardening is 2 to 6 MPa.

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