BS 8006-2:2011+A1:2017
$215.11
Code of practice for strengthened/reinforced soils – Soil nail design
| Published By | Publication Date | Number of Pages |
| BSI | 2017 | 108 |
This part of BS 8006 gives recommendations and guidance for stabilizing soil slopes and faces using soil nails. Other methods of stabilization using reinforced soil methods are given in BS 8006โ1:2010 and both parts might be needed for complex structures.
Additional considerations might be required for unusually loaded or high soil nailed slopes, or where they interface with other structures.
Whilst BS EN 1997โ1:2004 specifically excludes soil nailing, this standard is intended to harmonize the design approach of soil nailing with other geotechnical structures designed using BS EN 1997โ1:2004.
The principal purpose of this standard is to provide design guidance, however, where knowledge of construction methodology is required for design purposes then appropriate paragraphs have been included. Construction guidance is given in execution standard BS EN 14490:2010. At the time of preparation of this standard, CEN Technical Committee TC341 is drafting a standard covering the testing of soil nails.
Structures and processes that are similar to soil nailing but not addressed in the standard are described in 2.3.6.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | Foreword |
| 9 | Section 1: General 1.1 Scope 1.2 Normative references |
| 10 | 1.3 Terms, definitions and symbols Figure 1 โ Terms used in this standard |
| 16 | Section 2: Soil nailing applications and construction considerations 2.1 General 2.2 Description of typical soil nail element components |
| 17 | Figure 2 โ Possible components of soil nail system, pre-bored and grouted, shown with rigid facing 2.3 Typical applications |
| 18 | Figure 3 โ Typical soil nailing applications (new cut and vertical cutting) Figure 4 โ Soil nail placement to preserve existing vegetation |
| 19 | Figure 5 โ Example of soil nailing of an existing retaining structure |
| 20 | Figure 6 โ Example of soil nailing of an embankment 2.4 Construction design considerations |
| 21 | Figure 7 โ Bulk excavation and requirement to check overall stability |
| 22 | Figure 8 โ Excavation tolerances |
| 25 | Section 3: Suitability of ground and groundwater conditions 3.1 General 3.2 Understanding the site geology |
| 26 | 3.3 General requirements for suitability of soils and rocks for soil nailing 3.4 Suitability of cohesive soils for soil nailing |
| 27 | Table 1 โ Summary of ground conditions best suited and less well suited to soil nailing |
| 29 | Figure 9 โ Examples of the effect of pre-existing shear surfaces on soil-nailed structures |
| 30 | Figure 10 โ Problems caused by granular material in glacial till |
| 31 | 3.5 Suitability of granular soils for soil nailing |
| 32 | 3.6 Suitability of weak rocks for soil nailing 3.7 Suitability of fill for soil nailing |
| 33 | Figure 11 โ Adverse effects of jointing and bedding on cut slopes in weak or weathered rock |
| 35 | 3.8 Effects of groundwater on soil nailing |
| 36 | Table 2 โ Principal types and suitability for soil nailing of non-engineered fill |
| 38 | Figure 12 โ Effect of groundwater on wall facing 3.9 Effects of underlying geological features on soil nailing |
| 39 | 3.10 Site investigation 3.11 Soil-nailing related site investigation โ Field trials 3.12 Soil-nailing related site investigation โ Chemical testing |
| 40 | 3.13 Preliminary assessment of degradation risk |
| 41 | Table 3 โ Typical corrosion rates for uncoated steel in undisturbed ground conditions 3.14 Detailed assessment of degradation risk for buried components 3.15 Detailed assessment of degradation risk for exposed components and surfaces |
| 42 | Table 4 โ Description of typical atmospheric environments related to the estimation of corrosivity categories (Copy of Table C.1 from BS EN ISO 9223:2012 [15]) |
| 44 | Section 4: Basis for design 4.1 Design method |
| 45 | Figure 13 โ Typical dimensions of soil nailing applications based on slope |
| 46 | Figure 14 โ Relevant modes of ultimate and serviceability limit states |
| 47 | Figure 15 โ Geometry and dimensions of a soil nailed slope |
| 48 | Table 5 โ Partial factors for soil nail design |
| 49 | 4.2 Analysis of stability |
| 50 | Figure 16 โ Ultimate limit state modes of failure |
| 51 | Figure 17 โ Slip circle method of slices |
| 53 | Figure 18 โ Methods of resolving nail force and degree of conservatism |
| 54 | Figure 19 โ Two-part wedge |
| 57 | 4.3 Soil nail pullout resistance Figure 20 โ Mobilization of bond stress as a function of relative soil-nail movement |
| 58 | Figure 21 โ Limiting nail strength envelope |
| 60 | Figure 22 โ Effect of far field stress on mobilized bond stress Figure 23 โ Modification of interface stresses due to far field stress changes |
| 61 | Figure 24 โ Relationships between radial friction normalized by vertical effective stress for a range of characteristic friction angle |
| 62 | Figure 25 โ Modification of local interface stresses due to nail installation effects |
| 63 | Figure 26 โ Effect of test length and axial stiffness on measured average bond |
| 66 | Table 6 โ Ultimate limit state approach to deriving design values 4.5 Soil nail element design |
| 67 | 4.6 Influence of durability and degradation on the choice of nail tendon |
| 70 | Table 7 โ Types of stainless steel Table 8 โ Types of glass fibre (after Littlejohn [30]) |
| 74 | Figure 27 โ A 25 mm diameter steel tendon with a 40 mm diameter impermeable duct |
| 75 | Figure 28 โ A centralizer to provide cover to a coated nail to reduce the risk of damage to the coating during installation Figure 29 โ A stainless steel self-drilling tendon complete with drill bit, hollow tendon, coupler and head plate |
| 78 | Table 9 โ Summary of recommendations for different soil nailing systems in relation to different categories of risk 4.7 Design of facing |
| 83 | Figure 30 โ Calculation of required nail plate size for a given design nail force |
| 84 | Figure 31 โ Calculation of design loading acting on the rear of hard facing |
| 86 | Figure 32 โ Calculation of design loading acting on a simple flexible facing |
| 87 | Figure 33 โ Calculation of tension and deformation in flexible facing for a given design loading |
| 89 | Figure 34 โ Requirements of a complex flexible facing 4.8 Drainage |
| 90 | Figure 35 โ Typical types of drainage for soil nailing |
| 91 | Figure 36 โ Typical surface water interceptor detail above a steep soil-nailed slope Figure 37 โ Example of a raking drain in a steep soil-nailed slope |
| 92 | Figure 38 โ Typical detail for a weep hole in a steep soil-nailed wall |
| 93 | Section 5: Serviceability and movements 5.1 Serviceability limit state |
| 94 | 5.2 Serviceability limit state analysis 5.3 Estimation of movement โ General 5.4 Use of empirical relationships |
| 95 | Table 10 โ Displacements at the top of steep soil nailed structures |
| 96 | 5.5 Numerical modelling 5.6 Case studies |
| 97 | Section 6: Design verification 6.1 Testing |
| 98 | Table 11 โ Type of soil nail test (from BS EN 14490:2010) Table 12 โ Recommended test frequency (from BS EN 14490:2010) |
| 99 | 6.2 Nail pullout resistance |
| 100 | Table 13 โ Criteria for static loading of soil nails |
| 101 | Figure 39 โ Schematic layout of the nail load test system |
| 102 | Table 14 โ Values of correlation factor |
| 103 | 6.3 Materials testing 6.4 Other tests 6.5 Monitoring 6.6 Monitoring during construction 6.7 Long-term or post-construction monitoring |
| 104 | Section 7: Maintenance |
| 105 | Bibliography |
