Application case analysis of SINOROCK self-drilling anchor--Huangshan Pedestrian Mall foundation support

Time:2024-10-15From:sinorock View:

Self-drilling anchor systems have become a cornerstone in modern construction, especially in foundation support projects where complex geological conditions present numerous challenges. These advanced systems, such as SINOROCK's self-drilling hollow anchor bars, offer practical solutions for stabilizing unstable rock masses and improving construction efficiency. One prominent case study that highlights the benefits of this technology is the Huangshan Pedestrian Mall foundation support project. In this project, the use of R38 self-drilling anchor bolts successfully overcame drilling difficulties in the round gravel layer, significantly enhancing construction productivity and reducing overall costs.

1. Background and Challenges

Overview of the Huangshan Pedestrian Mall Project

The Huangshan Pedestrian Mall is a significant infrastructure development project in China, covering an expansive planned area of approximately 36,372 square meters. With the building height reaching 13 meters, the foundation support was of paramount importance to ensure structural integrity. Given the diverse and complex geological profile of the site, the project posed a series of technical challenges that required innovative solutions to ensure safe and efficient construction.

Geological Composition and Construction Challenges

The site’s rock and soil layers presented a difficult geological landscape. From top to bottom, the layers consisted of mixed fill, silt, fine sand, round gravel, strongly weathered siltstone, strongly weathered phyllite, moderately weathered siltstone, moderately weathered phyllite, and significant amounts of construction waste. The presence of such varied rock and soil types complicated the foundation support work, particularly in terms of hole drilling in the round gravel layer.

The round gravel layer posed a significant challenge for traditional drilling methods. Due to its loose composition, drilling without additional support would result in unstable boreholes. This necessitated the use of casings, which were both inefficient and costly. Additionally, the casing method risked causing infrasound damage to the surrounding area, raising concerns about environmental impact and potential harm to nearby structures. The complexity of these conditions meant that a more advanced solution was needed, leading the construction team to adopt SINOROCK’s R38 self-drilling anchor bolts.

2. Construction Plan

Technical Requirements and Initial Plan

The primary objective of the construction was to provide stable foundation support by ensuring that the hollow anchor rods penetrated the tangent supporting pile and drilled through the gravel and strongly weathered layers. The conventional casing method, though effective in some scenarios, proved to be inadequate in the face of the round gravel layer’s instability.

The initial plan of using casings was soon abandoned due to the inefficiencies and risks associated with it. Instead, SINOROCK’s self-drilling anchor system was chosen for its ability to simultaneously drill and grout. This change not only simplified the drilling process but also enhanced the overall effectiveness of the foundation support. The simultaneous drilling and grouting process allowed for better soil consolidation around the anchor bar, ultimately improving the anchoring force and soil stability.

SINOROCK Self-Drilling Anchor Solution

The construction team employed the HYZ133-100A drilling rig, paired with SINOROCK’s R38 self-drilling hollow anchor bar and an ESF R38/90 drill bit. Rotary percussion drilling was used to achieve the necessary drilling depth of 18 meters. The grout was injected through the hollow core of the anchor bar with a water-cement ratio between 0.5 and 0.55, and the grouting pressure was maintained between 0.3 and 0.5 MPa. The compressive strength of the grout body reached 20 MPa, ensuring a strong and stable foundation.

This simultaneous drilling and grouting technique allowed for improved soil quality surrounding the anchor bar and enhanced the overall anchoring force. The efficiency of this method was demonstrated by the construction team's ability to drill up to 500 meters in a single 12-hour shift, significantly reducing the time and labor required compared to traditional methods.

3. Testing and Quality Assurance

Testing Procedures

To ensure that the anchors met the design specifications, rigorous testing was carried out after grouting was completed. The process involved installing the breast beam, plate, wedge, and hex nut in sequence to prepare the anchors for testing. The design pull-out force was set at 15 kN/m, with a minimum of 3% of the total number of anchors tested, and no fewer than five anchors were subjected to the pull-out test.

The target pulling-out force for the anchors was 270 kN, and each tested anchor met or exceeded this requirement. These results confirmed the effectiveness of the SINOROCK self-drilling anchor system in providing the necessary foundation support under challenging geological conditions. Additionally, the full grouting process contributed to improved bond strength between the anchor and surrounding soil, further enhancing the stability of the foundation.

Importance of Comprehensive Testing

Comprehensive testing is a critical component of any construction project, particularly in foundation support work where safety and durability are paramount. In the Huangshan Pedestrian Mall project, the thorough testing procedures ensured that the foundation could withstand the designed loads and that the anchors provided long-term stability.

anchoring test

Testing not only verifies the strength of the installed anchors but also serves as a quality assurance measure for the construction process. By confirming that the anchors met the required specifications, the project team could proceed with confidence, knowing that the foundation would perform as expected under various conditions.

4. Project Summary and Key Benefits of SINOROCK Self-Drilling Anchors

Summary of the Project

The original design for the Huangshan Pedestrian Mall foundation support relied on traditional casing drilling methods. However, due to the difficulties encountered in drilling through the round gravel layer, the project team switched to SINOROCK’s self-drilling anchor bolts. This decision proved to be highly beneficial, as the self-drilling system provided a more efficient and cost-effective solution for stabilizing the foundation.

The self-drilling anchor system solved the problem of anchoring in loose rock and soil, a common issue in projects involving round gravel layers. By simultaneously drilling and grouting, the system ensured that the grout filled the surrounding soil completely, improving the overall stability of the foundation. Moreover, the efficiency of the self-drilling process reduced labor costs and shortened the construction timeline, making it a more attractive option for future projects.

Benefits of SINOROCK Self-Drilling Anchor Systems

The SINOROCK self-drilling anchor system offers several key advantages over traditional methods, making it a preferred choice in foundation support projects:

1. Improved Efficiency: The simultaneous drilling and grouting process eliminates the need for casing and reduces the number of steps required to install the anchors. This leads to faster project completion times and reduced labor costs.

2. Cost-Effectiveness: By simplifying the drilling process and reducing the need for additional materials such as casing, the self-drilling anchor system lowers overall project costs.

3. Enhanced Stability: The full grouting process ensures that the anchor is securely bonded to the surrounding soil, improving the stability and load-bearing capacity of the foundation.

4. Versatility in Challenging Conditions: Self-drilling anchor systems are particularly effective in complex geological environments, such as the round gravel layer encountered in the Huangshan Pedestrian Mall project. These systems can easily penetrate loose, weathered rock layers, providing reliable support in difficult conditions.

5. Environmental Impact: Traditional casing methods can cause infrasound damage to the surrounding area, potentially affecting nearby structures and the environment. Self-drilling anchors mitigate this risk by eliminating the need for casing and reducing the overall disturbance to the surrounding soil.

5. Current Industry Trends and the Role of Self-Drilling Anchors

Growing Demand for Advanced Construction Solutions

As construction projects become increasingly complex, the demand for advanced foundation support solutions like self-drilling anchor systems continues to grow. Urban development projects, infrastructure upgrades, and environmental challenges are driving the need for more efficient and reliable anchoring technologies.

In particular, the construction industry is moving towards more sustainable and cost-effective solutions that minimize environmental impact and reduce project timelines. Self-drilling anchors, with their ability to improve construction efficiency and provide robust support in challenging geological conditions, are well-positioned to meet these demands.

The Role of SINOROCK in the Industry

SINOROCK has established itself as a leader in the development and manufacture of self-drilling anchor systems. The company’s products are designed to meet the evolving needs of the construction industry, offering innovative solutions that improve project efficiency and reduce costs. In projects like the Huangshan Pedestrian Mall foundation support, SINOROCK’s self-drilling anchors have demonstrated their value by overcoming significant construction challenges and delivering reliable, long-lasting results.

Return The List