Clay core wall cofferdam
By constructing a clay core cofferdam on the bedrock and riverbed sand and gravel layer, combined with earth and stone slag and geomembrane, the problems of easy water seepage and high cost of the cofferdam are solved, and a low-cost and efficient anti-seepage effect is achieved, which is suitable for river construction in mountainous areas.
Patent Information
- Application Number
- CN202422599125.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2034-10-28
AI Technical Summary
The existing cofferdam is prone to water seepage under conditions of large water volume and sandy soil, and the concrete cofferdam is expensive, uneconomical, and affects the progress of the project.
A clay core cofferdam structure is adopted, including a clay core wall located on the bedrock and soil and rock slag distributed on both sides thereof, combined with geomembrane and sandbags, and designed with a trapezoidal cross-section to enhance the anti-seepage function.
The construction on bedrock in mountainous areas and riverbed gravel layers is simple and low-cost, and has good anti-seepage effect, ensuring the rapid progress of the project.
Smart Images
Figure CN223410188U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of cofferdams, and specifically relates to a clay core wall cofferdam. Background Art
[0002] The cofferdam construction in mountainous rivers mostly adopts earth-rock cofferdam, grass-soil cofferdam, bagged earth cofferdam, concrete cofferdam and other cofferdams. Earth-rock cofferdam, grass-soil cofferdam and bagged earth cofferdam are prone to water seepage in conditions with large water volume and sandy soil. Concrete cofferdam is expensive and uneconomical, which is not conducive to the progress of the project. Utility Model Content
[0003] The purpose of this application is to overcome the defects of existing cofferdams that are prone to water seepage and high cost.
[0004] In order to achieve the above-mentioned purpose, the present application proposes a clay core wall cofferdam suitable for construction on bedrock and riverbed sand and gravel layers, wherein the cofferdam comprises a clay core wall 1 and soil and rock slag 2; wherein,
[0005] The clay core wall 1 is a wall built with clay, located on the bedrock, and is divided into an upper and lower part. The lower part of the clay core wall 1 is flush with the upper surface of the riverbed gravel, or within 50 cm above the upper surface of the riverbed gravel. The upper part of the clay core wall 1 is flanked by soil and rock slag 2.
[0006] The soil and rock slag 2 is distributed on the riverbed sand and gravel and on both sides of the clay core wall 1, and its upper surface is flush with the top of the clay core wall 1; the soil and rock slag 2 has a certain slope away from both sides of the clay core wall 1.
[0007] As an improvement to the above cofferdam, the lower half of the clay core wall 1 gradually widens from bottom to top;
[0008] The bottom of the upper half of the clay core wall 1 is the same width as the top of the lower half;
[0009] The width of the upper part of the clay core wall 1 gradually decreases from the bottom to the top.
[0010] As an improvement to the above-mentioned cofferdam, the top width of the lower half of the clay core wall 1 is 2-2.5 times the top width of the upper half.
[0011] As an improvement to the above cofferdam, the slope of the soil and rock slag 2 away from the clay core wall 1 is 1:2.
[0012] As an improvement to the above cofferdam, the cofferdam further comprises:
[0013] The geomembrane 3 covers the side of the soil and rock slag 2 in contact with water; the geomembrane 3 extends a distance away from the clay core wall 1 at the bottom of the soil and rock slag 2, and extends a distance toward the clay core wall 1 at the top of the soil and rock slag 2.
[0014] As an improvement to the above cofferdam, the cofferdam further comprises:
[0015] Several sandbags 4 are placed on the geomembrane 3 extending from the top and bottom of the soil and rock slag 2.
[0016] As an improvement to the above-mentioned cofferdam, the clay of the clay core wall 1 has a certain water content. The test shows that the water content of the clay meets the construction standard by forming a ball when held in the hand and breaking into pieces when touched to the ground.
[0017] Compared with the prior art, the advantages of this application are:
[0018] It is suitable for clay core wall cofferdams on bedrock and sand and gravel layers in mountainous areas. It has a simple structure, reasonable design, convenient construction, good construction effect, can be completed quickly on the construction site, and has low construction cost. It has a strong anti-seepage function. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Shown is a structural diagram of Example 1 of the present application;
[0020] Figure 2 Shown is a structural diagram of Example 2 of the present application;
[0021] Figure 3 Shown is a schematic diagram of the clay core cofferdam construction process.
[0022] Figure ID:
[0023] 1. Clay core wall 2. Soil and stone slag
[0024] 3. Geomembrane 4. Sandbag
[0025] 5. Riverbed sand and gravel 6. Bedrock DETAILED DESCRIPTION
[0026] The technical solution of this application is described in detail below with reference to the accompanying drawings.
[0027] like Figure 1 As shown, the present application provides a clay core wall cofferdam suitable for cofferdam construction on bedrock in mountainous areas and riverbed sand and gravel layers. The clay core wall cofferdam includes:
[0028] Clay core wall 1: This wall is constructed of clay and is located above bedrock 6. It consists of two parts, upper and lower. The lower part is flanked by riverbed gravel 5, or within 50 cm of the upper surface of the riverbed gravel 5. The lower part gradually widens from bottom to top. The upper part is flanked by soil and rock slag 2. The bottom is the same width as the top of the upper part, and the width gradually decreases from bottom to top. The top width of the lower part is 2-2.5 times the width of the top of the upper part.
[0029] Soil and rock slag 2: distributed on the riverbed sand and gravel 5, on both sides of the clay core wall 1, with the upper surface flush with the top of the clay core wall 1; its two sides facing outward have a certain slope. Preferably, the slope is 1:2.
[0030] The cofferdam adopts a clay core wall 1 for anti-seepage. The construction method is to dig to the bedrock 6 with an excavator, clean it, fill it with clay in layers and compact it tightly.
[0031] The cofferdam earth and rock slag 2 is filled with 1.6m 3 Backhoes excavate the slag, dump trucks transport it, and bulldozers level and compact it. The clay core wall (1) rises simultaneously with the soil and rock slag (2). During cofferdam construction, riverbed sand and gravel (5) are removed from the clay core wall (1) to prevent water seepage.
[0032] like Figure 2 FIG. 1 shows another embodiment of the clay core cofferdam of the present application. Based on the embodiment 1, this embodiment lays a geomembrane 3 on the side of the soil and rock slag 2 that contacts water.
[0033] The geomembrane 3 covers the entire slope of the soil and rock slag 2 that contacts the water. It extends a distance away from the clay core wall 1 at the bottom of the soil and rock slag 2 and a distance toward the clay core wall 1 at the top of the soil and rock slag 2. Several sandbags 4 are placed on the geomembrane 3 extending from the top and bottom of the soil and rock slag 2 to prevent the geomembrane 3 from moving.
[0034] The geomembrane 3 can further prevent water from penetrating into the cofferdam.
[0035] The construction process of the clay core cofferdam includes the following steps:
[0036] ⑴Construction method
[0037] The cofferdam filling materials are transported by 15T dump trucks.
[0038] The backfill of earth and rock slag in the cofferdam adopts the layered synchronous rising construction method, first laying the material in the upstream area, then the core wall clay, and then laying the material in the downstream area and compacting it all at once.
[0039] ⑵Technical measures
[0040] 1) Filling construction procedures
[0041] Clean the foundation surface → measure and lay out the filling working surface → lay out the boundary lines of the partitions → spread the materials → control the spreading and layer thickness → sprinkle water → roll → quality inspection → proceed to the next process.
[0042] 2) Clearing the foundation
[0043] Before backfilling, the foundation of the filling section must be cleaned first. Trees, plant roots, branches, leaves, waste bricks and rubble, cement slag, and other debris in the foundation must be completely removed. Only after the foundation treatment has passed the inspection can the earthwork backfill be carried out. The base of the clay core wall must be cleaned to prevent water seepage from the bottom.
[0044] 3) Measurement and layout of filling working surface
[0045] Stake out and measure the outer edge of the cofferdam and the edge of the clay core wall;
[0046] 4) Backfill mining and transportation
[0047] Backfill earth and stone use foundation excavation materials, clay materials are taken from the soil yard, and 1.6m 3 The excavator was transported to the construction site with a 15T dump truck. The clay soil's moisture content was tested before compaction to determine the optimal moisture content and minimum number of compaction passes required to meet density requirements. The difference between the optimal moisture content and the construction moisture content of clay soil can be controlled within ±2%. The soil should be able to form a ball when held in the hand and break into pieces when dropped to the ground. Excessive moisture should be loosened, air-dried, and replaced with backfill. If the soil is too dry, it should be pre-moistened with water. When the moisture content is low, measures such as increasing the number of compaction passes or using high-powered compacting machinery can also be adopted. In dry weather, the construction speed should be accelerated to minimize moisture loss. For gravel-like fillers, they should be thoroughly wetted with water before rolling to improve compaction.
[0048] 5) Paving materials
[0049] The backfill of the cofferdam soil and rock slag material adopts the layered synchronous rising construction method, first paving the upstream area → core wall clay → then paving the downstream area and rolling it all at once.
[0050] The backfill material is spread by T220 bulldozer. The length of the filling section shall not be less than 20m, and the soil shall be spread in layers with a normal thickness of no more than 30-50cm each time. The paving construction shall start from the lowest part and spread the material from bottom to top in horizontal layers. Filling along the slope is not allowed. During construction, the adjacent segmented working surfaces shall rise evenly to reduce construction joints. The maximum thickness of the paving material shall not exceed 50cm. During construction, unified management shall be strengthened, the working surface shall be uniformly spread and compacted, and records shall be kept. The processes of transporting, loading and unloading, spreading, and compacting the backfill material shall be carried out continuously. When constructing the second layer, the core wall shall be roughened with an excavator.
[0051] Fill compaction (tamping) method:
[0052] The filling starts from the lowest point, and is spread and compacted layer by layer from bottom to top. The schematic diagram of the laying sequence is as follows:
[0053] First, clean the foundation surface of the clay core wall backfill at the bedrock, then spread the clay material backfill, and tamp the material in layers according to the thickness of the riverbed sand and gravel layer (if the thickness here is not more than 30-50cm, do not backfill in layers, if the thickness here is more than 50cm, backfill in layers here); in order to ensure that there is no leakage in the clay core wall between the riverbed sand and gravel and the bedrock, widen the width of the clay core wall in the riverbed sand and gravel (about 2-2.5 times the width of the upper opening), tamp and fill densely, and then use an excavator to roughen the surface; then lay the riverbed sand and gravel surface The process begins with laying soil and rock slag on one side of the riverbed gravel → laying the clay core wall on top of the riverbed gravel → laying soil and rock slag on the other side of the riverbed gravel surface. After this layer of material is laid, it is uniformly rolled and compacted. After compaction, the surface of the clay core wall is roughened. Paving, backfilling, and compaction are carried out layer by layer in this order. The clay core wall is widest 30-50 cm above the riverbed gravel surface (approximately 2-2.5 times the width of the upper opening) to ensure no leakage between the riverbed gravel and backfill soil and soil and rock slag, achieving the water-retaining effect of cofferdam construction. According to seepage pressure, the clay core wall decreases as it is built upwards, so the section above the riverbed gravel has a trapezoidal cross-section.
[0054] Fill compaction (tamping) method: Fill the soil starting from the lowest point, and spread the filling layer by layer from the bottom to the entire width, and compact it by rolling. Before rolling with a rolling machine, it is advisable to first use a light bulldozer or grader to level the soil, and pre-compact at a low speed to make the surface flat; use a vibrating flat roller for compaction, and the stone slag or crushed stone soil should be statically compacted first and then vibrated. When compacting the fill with a rolling machine, the driving speed should be controlled. Generally, the speed of the flat roller and vibrating roller should not exceed 2km / h, and the number of compaction passes should be controlled. Use a road roller to compact the fill. The fill thickness should not exceed 25-30cm (the soil and stone slag should not exceed 50cm). The rolling direction is from both sides to the middle. The overlapping width of the roller is about 15-25cm each time to avoid missing pressure. During operation, the roller edge is greater than 50cm away from the edge of the fill. Where the slope edge cannot be compacted, it is supplemented by manual or small compacting machines.
[0055] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit the scope of the present invention. Although this application has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should be encompassed by the claims of this application.
Claims
1. A clay core cofferdam suitable for construction on bedrock and riverbed gravel layers, characterized in that: The cofferdam comprises a clay core wall (1) and soil and rock slag (2); wherein, The clay core wall (1) is a wall built with clay, located on the bedrock, and is divided into an upper and lower part; the lower part of the clay core wall (1) is flush with the upper surface of the riverbed gravel, or is within 50 cm higher than the upper surface of the riverbed gravel; the upper part of the clay core wall (1) is flanked by soil and rock slag (2); The soil and rock slag (2) is distributed on the riverbed sand and gravel and on both sides of the clay core wall (1), and its upper surface is flush with the top of the clay core wall (1); the soil and rock slag (2) has a certain slope away from both sides of the clay core wall (1).
2. The clay core cofferdam according to claim 1, characterized in that: The lower half of the clay core wall (1) gradually widens from bottom to top; The bottom of the upper part of the clay core wall (1) is the same width as the top of the lower part; The width of the upper part of the clay core wall (1) gradually decreases from the bottom to the top.
3. The clay core cofferdam according to claim 2, characterized in that: The top width of the lower half of the clay core wall (1) is 2-2.5 times the top width of the upper half.
4. The clay core cofferdam according to claim 1, characterized in that: The slope of the soil and rock slag (2) away from the clay core wall (1) is 1:
2.
5. The clay core cofferdam according to claim 1, characterized in that: The cofferdam further comprises: A geomembrane (3) covers the side of the soil and rock slag (2) in contact with water; the geomembrane (3) extends a distance away from the clay core wall (1) at the bottom of the soil and rock slag (2), and extends a distance toward the clay core wall (1) at the top of the soil and rock slag (2).
6. The clay core cofferdam according to claim 5, characterized in that: The cofferdam further comprises: A plurality of sandbags (4) are placed on the geomembrane (3) extending from the top and bottom of the soil and rock slag (2).
7. The clay core cofferdam according to claim 1, characterized in that: The clay of the clay core wall (1) has a certain water content. The test results show that the water content of the clay meets the construction standard: the clay can be shaped into a ball when held in the hand and can break into pieces when dropped to the ground.