Pile foundation protection wall protection structure under thick pebble covering layer
By using nano-silicate waterproofing agent to reinforce the pebble layer and spraying cement slurry to protect the wall structure, the problem of easy collapse during drilling in karst areas was solved, stable pile foundation wall protection was achieved, and construction efficiency and quality were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-07
- Publication Date
- 2026-05-15
AI Technical Summary
In karst areas with thick pebble overburden, the borehole wall is prone to instability during drilling, leading to problems such as collapse and diameter reduction. Traditional wall protection methods are unstable, affecting construction progress and costs.
A nano-silicate waterproofing agent is injected into the pebble covering layer to solidify and form a reinforced pebble layer. A protective wall structure with a thickness of not less than 20cm is formed on the inner wall of the pile hole by jet spraying cement grout, which is embedded 15-20cm above and below the pebble layer to improve the bonding strength and water resistance between the pebbles.
It significantly improves the bonding strength and water resistance of the pebble layer, reduces the probability of borehole collapse caused by borehole wall instability, and ensures smooth construction and pile foundation quality.
Smart Images
Figure CN224243849U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of pile foundation construction technology, and in particular to a pile foundation retaining wall protection structure under a thick pebble cover layer. Background Technology
[0002] Karst areas, also known as karst landform areas, refer to geologically rich regions rich in soluble rocks or minerals. In some karst areas, the geological morphology is particularly complex, characterized by well-developed caves, widespread pebble layers, and interwoven dissolution fissures. The pebble layers are primarily composed of gravel and pebbles of varying sizes, lacking effective cementation between particles, with a porosity as high as 25%-40% and a high permeability coefficient (approximately 1×10⁻⁶). -2 This loose structure (cm / s) makes the borehole wall extremely prone to instability during drilling, leading to problems such as collapse and diameter reduction. In severe cases, it can even cause stuck drill or buried drill accidents, resulting in delays in the construction period and increased construction costs.
[0003] Traditional methods of constructing cast-in-place piles involve drilling with mud slurry for wall protection and casing, but these methods suffer from unstable wall protection and even hole collapse. In addition, they also have problems such as long drilling cycles and complex equipment. Therefore, for pile foundations that penetrate thick gravel overburden, forming a stable pile foundation wall protection structure is a crucial factor affecting the smooth progress of construction and the quality of the pile foundation. Utility Model Content
[0004] This utility model discloses a pile foundation retaining wall protection structure under a thick pebble cover layer, which reinforces the inner wall of the pile hole segment that passes through the thick pebble cover layer, thus helping to ensure smooth construction and pile foundation quality.
[0005] To achieve the above objectives, the technical solution of this utility model is as follows:
[0006] A protective structure for pile foundation retaining walls under a thick pebble overburden layer, comprising:
[0007] The reinforced pebble layer is formed by injecting a nano-silicate waterproofing agent into the pebble covering layer and consolidating it, and is located on the periphery of a certain segment of the pile hole;
[0008] The retaining wall structure is formed by cement grouting solidified on the inner wall of the pile hole through the pebble cover layer, with a thickness d of not less than 20cm.
[0009] Preferably, the segment of the pile hole that passes through the reinforced pebble layer is expanded outward by 2d relative to the designed diameter of the pile hole, so as to accommodate the protective wall structure on the inner sidewall of the reinforced pebble layer, so that the diameter of the pile hole meets the requirements.
[0010] Preferably, the protective wall structure is embedded downward into the base layer below the reinforced pebble layer, and the downward extension height is not less than 15cm.
[0011] Preferably, the protective wall structure is embedded upward into the upper layer of pebbles above the reinforced pebble layer, and the upward extension height is not less than 15cm.
[0012] More preferably, the thickness of the protective wall structure is 25 cm.
[0013] More preferably, the protective wall structure is embedded downward into the base layer below the reinforced pebble layer, extending downward to a height of 20cm.
[0014] More preferably, the protective wall structure is embedded upward into the upper layer of pebbles above the reinforced pebble layer, extending upward to a height of 20cm.
[0015] Preferably, the nano-silicate waterproofing agent is injected into the pebble covering layer and then vibrated and solidified by a vibrator to form the reinforced pebble layer.
[0016] Preferably, the cement grout is applied to and solidified on the inner wall of the pile hole passing through the pebble cover section by jet spraying.
[0017] The above-described pile foundation retaining wall protection structure under a thick pebble overburden layer has the following advantages:
[0018] (1) This utility model injects nano-silicate waterproofing agent into the pebble covering layer and then solidifies to form a reinforced pebble layer. After solidification, the compressive strength can reach 15-20 MPa, which significantly improves the bonding force between pebbles. It also has water resistance, corrosion resistance and erosion resistance, thereby reducing the probability of hole collapse caused by hole wall instability.
[0019] (2) This utility model uses a rotary jetting method to spray cement grout into the inner wall of the pile hole through the pebble covering layer, thereby completing the reinforcement of the pile and further reducing the probability of the hole collapse. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of this utility model.
[0021] In the diagram, 1 is the pile hole, 2 is the retaining wall structure, 3 is the clay layer, 4 is the reinforced pebble layer, and 5 is the limestone layer. Detailed Implementation
[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0023] In the description of this utility model, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use. They are only used to facilitate the description of this utility model and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0025] A pile foundation retaining wall protection structure under a thick pebble overburden, such as Figure 1 As shown, the structure includes a reinforced pebble layer 4 and a retaining wall structure 2. The reinforced pebble layer 4 is formed by injecting a nano-silicate waterproofing agent into the pebble covering layer and solidifying it. It is located on the periphery of a section of the pile hole 1. The nano-silicate waterproofing agent reinforces the pebble covering layer, and after curing, its compressive strength can reach 15-20 MPa. It can significantly improve the bonding force between pebbles and has water resistance, corrosion resistance, and erosion resistance, thereby reducing the probability of hole collapse due to hole wall instability. The retaining wall structure 2 is formed by cement grout solidifying on the inner wall of the pile hole 1 that passes through the pebble covering layer section. The cement grout is sprayed onto the inner wall of the pile hole 1 that passes through the pebble covering layer section by jet spraying, with a thickness d of not less than 20 cm. The cement grout can adhere to and solidify on the inner wall of the pile hole that passes through the pebble covering layer section by jet spraying, which can isolate the reinforced pebble layer 4 and the pile foundation to a certain extent, thereby completing the reinforcement of the pile periphery and further reducing the probability of hole collapse.
[0026] Preferably, the segment of pile hole 1 that penetrates the reinforced pebble layer 4 is extended outward by a thickness of 2d relative to the designed diameter of pile hole 1, so as to accommodate the retaining wall structure 2 on the inner sidewall of the reinforced pebble layer 4, ensuring that the diameter of pile hole 1 meets the requirements. That is, during drilling, when pile hole 1 penetrates the segment of the reinforced pebble layer 4, the hole diameter must be equal to the designed diameter of pile hole 1 + 2d. In this way, after the jet grouting of the retaining wall structure 2 is completed, the diameter of the pile hole still meets the design requirements.
[0027] More preferably, the thickness of the retaining wall structure 2 is designed to be 25cm, which can achieve a good reinforcement effect and will not affect the construction progress due to excessive reinforcement thickness.
[0028] During construction, after drilling to the target pebble layer, a high-pressure grouting pump is used to inject nano-silicate waterproofing agent into the pebble covering layer through pile hole 1. The grouting pressure is controlled at 0.5-1.0 MPa. After grouting, the hole is left to stand for 5 minutes to allow the grout to penetrate into the pores and solidify, thus forming a reinforced pebble layer 4. Then, a jet grouting pipe is inserted. After the jet grouting pipe sinks to the design depth, cement grout is sprayed into the part of pile hole 1 that corresponds to the reinforced pebble layer 4. The pipe is rotated while spraying grout. The process stops after the design thickness is reached. Then, the pile hole can be drilled downwards according to the established process.
[0029] Preferably, to further strengthen the pile hole retaining wall, the retaining wall structure 2 is embedded downwards into the base layer below the reinforced pebble layer 4, extending downwards to a height of not less than 15cm, such as... Figure 1 In this embodiment, the limestone layer 5 lies beneath the pebble cover layer. The hole is also expanded outwards at the top of the limestone layer 5, so that the diameter of this section reaches the designed diameter of the pile hole 1 + 2d. This allows for a section of protective wall structure to be jet-sprayed onto the top of the limestone layer 5, further reducing the impact of the pebble cover layer on the pile hole and better reinforcing the pile perimeter. More preferably, the downward extension height is 20cm, achieving a good reinforcement effect without affecting the construction progress due to excessive extension height.
[0030] Preferably, the protective wall structure 2 is embedded upwards into the upper layer of pebbles above the reinforced pebble layer 4, extending upwards to a height of not less than 15cm, such as... Figure 1 In this embodiment, the pebble cover layer is topped with a clay layer 3. The hole is also expanded outwards at the bottom of the clay layer 3, so that the diameter of this section reaches the designed diameter of the pile hole 1 + 2d. This allows for a section of protective wall structure to be jet-sprayed at the bottom of the clay layer 3, further reducing the impact of the pebble cover layer on the pile hole and better reinforcing the pile perimeter. More preferably, the upward extension height is 20cm, achieving a better reinforcement effect without affecting the construction progress due to excessive extension height.
[0031] Preferably, after the nano-silicate waterproofing agent is injected into the pebble covering layer, it is vibrated and solidified by a vibrator to form a reinforced pebble layer 4. Vibration by the vibrator can make the hole wall more compact and better prevent the hole collapse phenomenon.
[0032] For the preferred embodiment described above, this utility model further provides a construction method: drilling to the target pebble covering layer, and expanding the hole outward at a position at least 15cm above the pebble covering layer, with a hole diameter of the designed diameter of pile hole 1 + 2d; injecting nano-silicate waterproofing agent into the pebble layer through pile hole 1 using a high-pressure grouting pump, with the grouting pressure controlled at 0.5-1.0 MPa; after grouting, allowing it to stand for 5 minutes to allow the grout to penetrate into the pores and solidify, thereby forming a reinforced pebble layer 4; then drilling downward to at least 15cm below the reinforced pebble layer 4, and expanding the hole outward in the further downward drilling portion, with a hole diameter of the designed diameter of pile hole 1 + 2d; inserting a jet grouting pipe, and after the jet grouting pipe sinks to the designed depth, spraying cement grout into the outward-expanding portion of pile hole 1, while rotating the pipe, stopping after reaching the designed thickness; then the downward drilling of the pile hole can be carried out according to the established process.
[0033] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the present invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the present invention, as well as various different choices and variations. The scope of the present invention is intended to be defined by the claims and their equivalents.
Claims
1. A protective structure for pile foundation retaining wall under a thick pebble overburden layer, characterized in that... include: The reinforced pebble layer is formed by injecting a nano-silicate waterproofing agent into the pebble covering layer and consolidating it, and is located on the periphery of a certain segment of the pile hole; The retaining wall structure is formed by cement grouting solidified on the inner wall of the pile hole through the pebble cover layer, with a thickness d of not less than 20cm.
2. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1, characterized in that: The segment of the pile hole that passes through the reinforced pebble layer is expanded outward by 2d relative to the designed diameter of the pile hole, so as to accommodate the protective wall structure on the inner sidewall of the reinforced pebble layer, so that the diameter of the pile hole meets the requirements.
3. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 2, characterized in that: The protective wall structure is embedded downward into the base layer below the reinforced pebble layer, with a downward extension height of not less than 15cm.
4. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 2, characterized in that: The protective wall structure is embedded upward into the upper layer of pebbles above the reinforced pebble layer, and the upward extension height is not less than 15cm.
5. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1, characterized in that: The thickness of the protective wall structure is 25cm.
6. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1 or 3, characterized in that: The protective wall structure is embedded downward into the base layer below the reinforced pebble layer, extending downward to a height of 20cm.
7. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1 or 3, characterized in that: The protective wall structure is embedded upwards into the upper layer of pebbles above the reinforced pebble layer, extending upwards to a height of 20cm.
8. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1, characterized in that: The nano-silicate waterproofing agent is injected into the pebble covering layer and then vibrated and solidified by a vibrator to form the reinforced pebble layer.
9. The pile foundation retaining wall protection structure under a thick pebble overburden layer according to claim 1, characterized in that: The cement grout is applied to and solidified on the inner wall of the pile hole through the pebble overburden segment by jet spraying.