A method for constructing high-pressure rotary grouting interlocking piles in special soil

Abstract

The present invention discloses a method for constructing high-pressure rotary grouting interlocking piles in special soil, comprising the following steps: rotary drilling to form a hole, hole inspection, clay selection, clay replacement to form a hole, and high-pressure rotary grouting. By replacing the soil layer surrounding the pile foundation, the present invention successfully drills a pile hole that meets the design requirements in the special soil layer, creating prerequisites for subsequent construction and other foundation projects. The present invention can effectively cope with complex and changeable geological conditions, ensure reliable foundation treatment effects in various soil layer environments, improve the adaptability and success rate of engineering construction, and at the same time protect surrounding existing buildings, underground pipelines and other facilities from construction disturbances.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and in particular relates to a construction technology of high-pressure rotary jet grouting piles, specifically a method for constructing high-pressure rotary jet grouting interlocking piles in special soil. Background Art

[0002] During construction, high-pressure jet grouting piles typically utilize direct drilling. When encountering unusual soil layers, such as pebbles and gravel, mechanical drilling techniques, such as geological drills or anchor drills, are often employed. However, pebbles and gravel are highly hard and abrasive, and the drill bits, drill rods, and other components of geological drills and anchor drills are subject to significant wear during the drilling process. Frequent replacement of drill bits and rods not only increases construction costs but also causes project delays. Furthermore, the uneven and densely packed particles in these unusual soil layers often make it difficult for geological drills and anchor drills to effectively break and remove obstacles, leading to drill sticking and reduced construction efficiency.

[0003] Furthermore, due to the complexity of the strata, geological drills and anchor drills struggle to maintain a stable drilling trajectory, which can easily lead to problems such as skewed and irregular hole diameters. This is even more serious for interlocking pile construction, which can easily lead to problems such as pile body deflection, poor pile quality, and poor water-stopping. Furthermore, the stability of the hole walls in special soil layers is relatively poor, lacking the cohesive strength of clay. During the drilling and drilling process, factors such as mud pressure fluctuations and improper operation can easily cause hole wall collapse, affecting the quality of the hole and requiring rework. Summary of the Invention

[0004] The purpose of the present invention is to use traditional drilling methods to construct high-pressure rotary grouting interlocking piles in special soil layers, where problems such as pile body deviation, poor pile quality, poor water-stopping effect, and even a deadlock in which holes cannot be drilled often occur. A method for constructing high-pressure rotary grouting interlocking piles in special soil layers is provided to effectively cope with complex and changeable geological conditions, ensure reliable foundation treatment effects in various soil layer environments, improve the adaptability and success rate of engineering construction, and at the same time protect surrounding existing buildings, underground pipelines and other facilities from construction disturbances.

[0005] A method for constructing high-pressure rotary grouting interlocking piles in special soil comprises the following steps:

[0006] Step 1: Rotary drilling: Based on the special soil at the construction site and the design layout of the interlocking piles, select a rotary drilling rig with appropriate power and torque to perform rotary drilling. The drilling range must at least cover all the interlocking parts of the interlocking piles, and the drilling depth must be the same as the depth of the interlocking piles. The special soil may include sandy soil, pebble layers, gravel layers, and sandy soil layers.

[0007] Step 2: Hole inspection: Check the bottom of the hole excavated in step 1 to ensure there is no garbage or debris;

[0008] Step 3: Select clay: Select appropriate clay according to the on-site construction conditions; the clay plasticity index is 15-25, the clay content is 40%-60%, and the water content of the clay is controlled at 20%-30%;

[0009] Step 4: Clay replacement: Clean the hole and slowly fill the hole with clay. When it is filled to 1 / 4 of the height, start extracting the mud in the hole. Extract the mud while filling the clay until the hole is completely filled with clay. The process of extracting mud while filling the clay is conducive to the clay entering the gaps and corners of the hole wall better under the action of gravity and mud discharge, making the filling more dense and improving the stability and bearing capacity of the foundation.

[0010] Step 5: High-pressure rotary grouting: Drill holes according to the design plan, insert the grouting pipe to the bottom of the hole, inject grout with high pressure, and lift the pipe after the grouting is completed; after the high-pressure rotary grouting, at least the interlocking parts of each pile are in the area where the clay is replaced.

[0011] In further optimization, the range of holes formed in step 1 covers all the occlusal piles, and the number of holes formed is one or more.

[0012] Further optimization involves selecting appropriate clay based on the construction site conditions in step three. This involves selecting the clay's moisture content and plasticity based on the site's temperature and drought level. Lower temperatures lead to lower clay moisture content, while greater drought levels lead to higher clay moisture content and greater plasticity. For example, in cold northern regions, choosing clay with a low moisture content can reduce the risk of frost heave. In hot, arid regions, choosing clay with high plasticity can help resist rapid evaporation and reduce the likelihood of soil cracking.

[0013] For further optimization, in step 4, a mud pool is set up next to the hole for replacing clay, and the mud extracted from the hole flows into the mud pool.

[0014] In one solution, the pile bodies of the interlocking piles are arranged in rows, and the centers of the equal-height cross-sections of the pile bodies are on a straight line, and multiple holes are drilled, and the area of ​​each hole covers one interlocking part.

[0015] In one solution, the pile bodies of the interlocking piles interlock with each other, and if the centers of the equal-height cross-sections of the pile bodies are not on a straight line, a hole is drilled and the range of the hole covers all the interlocking piles.

[0016] Beneficial effects of the present invention:

[0017] 1. Enhanced hole wall stability: Special soil layers may have loose particles and poor cohesion, making the hole wall prone to collapse during direct drilling. However, after clay replacement, the viscosity of the clay can effectively fill the soil pores, enhancing the integrity and cohesion of the soil. This can better maintain the stability of the hole wall during the rotary drilling process, reduce the risk of hole collapse, and ensure construction safety and hole quality. For example, in sandy soil layers, the probability of hole wall collapse can be reduced by about 60% after clay replacement compared to direct drilling.

[0018] 2. Reduced Drilling Difficulty: Certain soil layers may contain hard impurities or possess a high density. Direct rotary drilling can lead to rapid drill bit wear and low drilling efficiency. However, clay replacement makes the soil more uniform and softer, allowing the drill bit to penetrate and break up the soil more easily, reducing equipment wear and increasing drilling speed. For example, in gravel-rich soil layers, clay replacement can increase drilling speed by approximately 40%.

[0019] 3. Improved pile bearing capacity: Clay replacement provides a more stable surrounding soil environment for the pile body. This enhances the friction and adhesion between the pile body and the clay, helping to more effectively transfer building loads to the deeper soil layers and improving the bearing capacity of the pile foundation. In contrast, drilling directly into specialized soil layers results in weaker interaction between the pile body and the surrounding loose soil, limiting bearing capacity. Actual engineering tests have shown that clay replacement can increase the bearing capacity of pile foundations by 30% to 50%.

[0020] 4. Improved pile quality: After clay replacement, continuous and stable cement slurry injection is ensured, ensuring pile integrity and enhancing the reliability and durability of high-pressure jet-jet piles. Furthermore, the verticality deviation of the drilling rig can be controlled within 1%, preventing pile tilt that could affect bearing capacity and stability.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the method in Example 1 of the present invention;

[0023] Figure 2 The arrangement of the occlusal piles and the hole-forming and clay-filling area in Example 2 of the present invention;

[0024] Figure 3 The arrangement of the occlusal piles and the hole-forming and clay-filling area in Example 3 of the present invention;

[0025] Reference numerals: 1. Interlocking pile; 2. Drilling and clay replacement area; 3. Interlocking part. DETAILED DESCRIPTION

[0026] Example 1

[0027] A method for constructing high-pressure rotary grouting interlocking piles in special soils includes the following steps after construction preparation, pile positioning, and equipment placement:

[0028] Step 1: Rotary drilling: Based on the special soil at the construction site and the design layout of the interlocking piles, a rotary drilling rig with appropriate power and torque is selected for rotary drilling. The drilling range covers all interlocking parts of the interlocking piles, and the drilling depth is the same as the depth of the interlocking piles. The special soil includes sandy soil layers, pebble layers, gravel layers, and sandy soil layers. In this embodiment, the pebble layer can be used, and the XCMG XR418F can be used. Torque: rated output torque 430kN·m, power: rated power 399kW.

[0029] like Figure 2 As shown, the pile bodies of the interlocking piles in this embodiment are arranged in rows, and the centers of the equal-height cross-sections of the pile bodies are on a straight line. Multiple holes are drilled, and the area of ​​each hole covers an interlocking part. This can save costs and achieve basic effects.

[0030] Step 2: Hole Inspection: Check the bottom of the hole excavated in Step 1 to ensure there is no garbage or debris.

[0031] Step 3: Select clay: According to the on-site construction conditions, select clay with a plasticity index of 15-25, a clay content of 40%-60%, and a water content of 20%-30%.

[0032] Step 4: Clay replacement: Clean the hole and slowly fill the clay into the hole. When it is filled to 1 / 4 of the height, start extracting the mud in the hole. Extract the mud while filling the clay until the hole is completely filled with clay.

[0033] Step 5: High-pressure rotary jetting: construct holes according to the design plan, insert the grouting pipe to the bottom of the hole, perform high-pressure jet grouting, and lift the pipe after the grouting is completed; after the high-pressure rotary jetting, the interlocking parts of the piles are in the area where clay is replaced.

[0034] Example 2

[0035] A method for constructing high-pressure rotary grouting interlocking piles in special soil, comprising the following steps after construction preparation, pile positioning, and equipment placement:

[0036] Step 1: Rotary drilling: Based on the special soil type at the construction site and the design layout of the interlocking piles, select a rotary drilling rig with appropriate power and torque to perform rotary drilling. The drilling range covers all interlocking parts of the interlocking piles, and the drilling depth is the same as the depth of the interlocking piles. The special soil type includes sandy soil, pebble layers, gravel layers, and sandy soil layers. In this embodiment, the sandy soil layer is used, so the XCMG XR138F can be used. Torque: Rated output torque 138kN·m; Power: Rated power 129kW.

[0037] like Figure 3 As shown, in this embodiment, the interlocking piles are set at the joints of the continuous wall, and the pile bodies are interlocked with each other to form a ring. If the centers of the equal-height cross-sections of the pile bodies are not on a straight line, a hole is drilled, and the range of the hole covers all the interlocking piles.

[0038] Step 2: Hole Inspection: Inspect the bottom of the hole excavated in Step 1.

[0039] Step 3: Select clay: According to the on-site construction conditions, select clay with a plasticity index of 15-25, a clay content of 40%-60%, and a water content of 20%-30%.

[0040] Step 4: Clay Replacement: Clean the hole and slowly fill it with clay. When it is 1 / 4 full, begin extracting mud from the hole. Continue to extract mud while filling the clay until the hole is completely filled with clay. Set up a mud pool next to the hole where the clay is replaced. The mud extracted from the hole flows into the mud pool.

[0041] Step 5: High-pressure rotary grouting: According to the design plan, holes are drilled in the area where the clay is to be replaced, the grouting pipe is inserted to the bottom of the hole, high-pressure grouting is performed, and the pipe is lifted after the grouting is completed; after the high-pressure rotary grouting, all piles are in the area where the clay is to be replaced.

[0042] The above embodiments are only partial embodiments of the present invention and cannot cover the entire present invention. Based on the above embodiments and drawings, those skilled in the art can obtain more implementation methods without paying any creative work. Therefore, these implementation methods obtained without paying any creative work should be included in the scope of protection of the present invention.

Claims

1. A method for constructing high-pressure rotary grouting interlocking piles in special soil, characterized in that: The following steps are involved: Step 1: Rotary drilling: Based on the special soil at the construction site and the design layout of the interlocking piles, select a rotary drilling rig with appropriate power and torque to perform rotary drilling. The drilling range must at least cover all the interlocking parts of the interlocking piles, and the drilling depth must be the same as the depth of the interlocking piles. The special soil may include sandy soil, gravel, and sandy soil layers. Step 2: Hole inspection: Check the bottom of the hole excavated in step 1 to ensure there is no garbage or debris; Step 3: Select clay: Select appropriate clay based on the on-site construction conditions; the clay plasticity index is 15-25, the clay content is 40%-60%, and the clay moisture content is controlled at 20%-30%. Selecting appropriate clay based on the on-site construction conditions includes: selecting the clay moisture content and clay plasticity based on the on-site temperature and drought level; The lower the temperature, the lower the moisture content of the selected clay; the greater the drought, the higher the moisture content and the stronger the plasticity of the selected clay; Step 4: Clay filling: Clean the hole and slowly fill the hole with clay. When the hole is filled to 1 / 4 of its height, start extracting the mud from the hole. While filling the clay, extract the mud until the hole is completely filled with clay. Step 5: High-pressure jet grouting: Drill holes according to the design plan, insert the grouting pipe to the bottom of the hole, inject grout with high pressure jets, and lift the pipe after the grouting is completed. After the high-pressure jet grouting, at least the interlocking parts of each pile are in the area where the clay is replaced; If the pile bodies of the occlusal piles are arranged in a row and the centers of the equal-height sections of the pile bodies are on a straight line, then multiple holes are drilled, and the area of ​​each hole covers one occlusal part; If the pile bodies of the interlocking piles interlock with each other and the centers of the equal-height sections of the pile bodies are not on a straight line, a hole is drilled and the range of the hole covers all the interlocking piles.

2. The method for constructing high-pressure rotary grouting interlocking piles in special soil according to claim 1, characterized in that: In step 4, a mud pool is set up next to the hole for replacing clay, and the mud extracted from the hole flows into the mud pool.

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