Soil Nail Support System for the Extension of A14 Trunk Road
Near the city of Cambridge in Great Britain, the trunk road between Girton and Histon is being widened by one lane per direction. The A14 is an important national highway that connects the Port of Felixstowe on the east coast with the British road network. Several steep sidehill cuts have to be comprehensively stabilized within the scope of the A14 widening. Self-drilling soil nail is a good helper for stabilizing slopes. Soil nails are installed top-down by the sidehill cuts that are carried out in individual stages, and the cut face is secured immediately as construction progressed. To install the...
The Successful Completion of Jingzhang High-speed Rail Donghuayuan Tunnel
At 17:30 on July 19th, 2018, with the pouring completion of the last slab lining concrete from Beijing to Zhangjiakou high-speed rail Donghuayuan tunnel, it marks that the tunnel used in cut and cover method without maintenance in the deep foundation pit of the longest water-rich area in China have been finished successfully. As a auxiliary project for the 2022 Winter Olympic Games in Beijing, Jingzhang high-speed rail is also the first intelligent high-speed railway in China. It is the first time that the automatic control precipitation and early warning system as well as new material robot spraying and waterproof...
Xi’an-Chengdu high speed railway entered the stage of full acceptance
On November 13th, the test train numbered 55601 departed from Xi’an North Station to Sichuan Jiangyou Station, marking the completion of the comprehensive acceptance stage before the high-speed railway entered into operation. After the opening, the train running time from Xi’an to Chengdu will be shortened from the current sixteen hours to three hours. On August 27, 2008, the State Council examined and approved the national overall plan for recovery and reconstruction after 2008 Sichuan earthquake, and Xi’an-Chengdu high speed railway was included. On October 27, 2012, the opening ceremony was held in Xi’an North Station. After five years of...
Some reasons for soil nailing wall’s safety and quality assurance
The soil nailing wall is a kind of technology for supporting and strengthening the in-situ soil. The soil nails are integrated with the soil around tightly, so that they can form into a type of composite soil, relying on the frictional force of contact surface. Based on the analysis of the constructional scheme of the national stadium, the key factors for controlling the quality of the construction were found. The quality system during the project should be managed strictly. And the diameter, length and strength of the anchorage ought to be executed exactly. This scheme provided reasons for the national...
Practice of hole drilling for soil nails
Soil nail construction involves the formation of holes followed by insertion of steel reinforcement, grouting and construction of soil-nail head typically in a recess on the slope surface. In Hong Kong, drilling of a soil-nail hole is commonly carried out by pneumatic percussive rigs (Plate 1) with air as the flushing medium. Temporary casing is normally not required in the typical saprolitic soils encountered in Hong Kong. In special circumstances, a more robust drilling rig, for example, the Odex type drilling equipment, is used for driving temporary casing into a hole concurrent with drilling to prevent the hole from collapsing...
Suitability of soil nailing with respect to soil types
As soil nail construction requires temporary stability in both the staged excavation and also the drilled hole stability, any soils with sufficient temporary self-support of about 2m sub-vertical height for minimum of 1 to 2 days and hole stability for minimum four hours are considered suitable ground for soil nailing. With the above criteria, the following soil types would be suitable for soil nailing: i. Stiff fine/cohesive soils ii. Cemented granular soils iii. Well graded granular soils with sufficient apparent cohesion of minimum 5kPa as maintained by capillary suction with appropriate moisture content iv. Most residual soils and weathered rock...
Design procedures of soil nail wall
The global stability of soil nail walls is commonly evaluated using two-dimensional limit equilibrium principles, which are used for conventional slope stability analyses. In practise, different shapes of the failure surface behind the soil nail wall have been considered in various methods to analyze the global stability of soil nail walls. Some of these shapes of the failure surfaces include: (1) planar , (2) bi-linear with a two-wedge slipping mass (e.g., German method as in Caltrans, 1991), (3) parabolic , (4) log spiral , and (5) circular . Numerical comparisons among different methods show that differences in the geometry of...
Design on soil-nailing wall Supporting of Foundation Pit in Bao Tou
Project Summary Proposed site is located in the north of the west of the east river road at bao tou . The side of the building has leisure square and commercial shop and underground garage on the north and south of village .The excavation depth is11 meters . Engineering geology According to the geological survey report, the soil is divided into miscellaneous fill,collapsible loess, silt, coarse sand. The physical and mechanical indexes of soil are shown in table 1. Table 1 Physical and mechanical properties of soils Layer soil type name Layer thickness(m) Severe(kN/m3) cohesive force(kPa) Angle of internal friction(°)...
Hampton Roads Bridge-Tunnel
The Hampton Roads Bridge-Tunnel (HRBT) is a 3.5-mile (5.6 km)-long Hampton Roads crossing for Interstate 64 and U.S. Route 60. It is a four-lane facility comprising bridges, trestles, man-made islands, and tunnels under the main shipping channels for Hampton Roads harbor in the southeastern portion of Virginia in the United States. It connects the historic Phoebus area of the independent city of Hampton near Fort Monroe on the Virginia Peninsula with Willoughby Spit in the city of Norfolk in South Hampton Roads, and is part of the Hampton Roads Beltway. To ease the traffic pressure, the expansion of the I-64...
Hollow bar soil nail of Sinorock can meet specific demands
Hollow bar soil nail can be installed in sites with weak rocks, loose soil, weathered layer, sand with stone layer and so difficult to create a hole in complex formation. The unconsolidated ground condition favor the technique of Hollow bar soil nail for fast and simple method of installed compared to the traditional method. For simultaneously drilling and injecting, it is usually performed in cases where the ground needs to be further improved or stabilized during installation. The installation of Hollow bar soil nail is simple and fast, the cost is less, and more important is that the Rock anchor...