variety of methods including traditional factor of safety approaches, including BS (BSI, ) and (BSI, ), CIRIA C (Phear et al, ) . Publisher: CIRIA. Soil nailing is a technique where either natural ground or fill material is reinforced by the insertion of slender tension-carrying elements called . thread Hi, My dissertation is within the scope of nailing in soils. I would like to consult the book mentioned in the topic title with the.

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In this chapter, the setup and instrumentation of the laboratory tests are first introduced. The changes of the vertical pressures at the other two earth pressure cells P-Cells 5 and 6 are not significant, as they are relatively c673 away from the drillhole. Join your peers on the Internet’s largest technical engineering professional community.

Hong Kong has a substantial portion of urban developments located on or near steep hillsides, resulting in the creation of 57, sizable man-made slopes. Regarding the effect of grouting pressure, Yeung et al. The model simulates all the procedures of the pullout tests for the cases of both unsaturated soil citia pressure grouting and saturated soil with pressure grouting. Privacy Policy Terms and Conditions. The magnitude of the normal stress increase, due to the effect of soil dilation, is dependent on a number of factors, such as the confining pressure, the soil relative density, the soil particle size and particle shape, the soil saturation condition.

In the composite representation, the reinforced soil structure is considered to be built from an orthotropic, locally homogeneous material with enhanced strength c367 stiffness properties.

It can be seen that the soil nail pullout resistance increases with the soil nail bending stiffness and it has a limit value when soil nail bending stiffness approaches to infinity in the soil nail reinforcement working system. As discussed in Chapter 5, the ciira stresses around the soil c6377 were observed to increase, to an extent, during saturation.

Soil nailing : best practice guidance

The shear modulus of the soil was assumed as 4 MPa by back analysis, considering the dimension effect of the reinforced steel bar. But this stress increase in the soil far away from the soil nail has a less distinct interface, such as at the locations of P-Cells 5 and 6.

The design concept of the soil nail pullout box is to enable the study in the laboratory of a short length of soil nail in cira passive zone of a soil nailed slope, as shown in Figure 4.


A general correlation may not be applicable to all sites Related to site-specific Coria to carry out a considerable number performance data of field pull-out tests during the design Pull-out Test c6377 Not feasible for small-scale cieia Time consuming Based on soil Generally not suitable for Hong Kong; Undrained Shear mechanics principles; Many factors that affect the pull-out Strength Easy to apply resistance are not accounted for. In Hong Kong, grouted soil nails have been used in most slope stabilization works c6637 the late s.

Chu performed a series of interface shear tests between a CDG soil and cement grout to investigate the shearing behaviour at the soil-grout interface. The controlled parameters include: It is clearly seen that a layer of soil adheres to the cement column of the soil nail during and after the soil nail pullout.

Many research projects have been undertaken. During the pullout of the soil nail, the variations of pullout force, pullout displacement, vertical earth pressures at six locations, pore water pressures at d637 locations and the strains in the soil nail, were automatically monitored and recorded.

Soil Nailing: C Best Practice Guidance by PHEAR, A –

Please enter recipient e-mail address es. The soil bearing stress was obtained by Eq. In the following section, the research and current knowledge of how different factors influence the pullout resistance are reviewed. It should be noted that some researchers argue that the direct shear tests could not represent the behaviour of the reinforcement in the slope Sawicki I would like to consult the book mentioned in the topic title with the following additional data: For example, the effective stress method, adopted in Hong Kong, does not account for factors including soil arching, soil dilatancy, soil saturation condition, roughness of drillhole surface, and grouting pressure.

Soil Nailing: C637: Best Practice Guidance

The main advantages and limitations are summarized in this section. Since P-Cell 5 and P-Cell 6 were placed far away from the soil nail, the variations of average effective stress at P-Cell 5 and P-Cell 6 could represent the changes of the effective overburden pressure.

Related to field Need a large number of field data to performance data; establish a reasonable correlation; Can better account for A general correlation may not be Pressuremeter influencing factors. The different initial earth pressures at P-Cells 1, 2, 3, and 4 before grouting are also observed in other test data cira in Figure 5.


In the present study, the pullout test results have shown that the pullout resistance is dependent on both overburden pressure and grouting pressure. Remember me on this computer. A schematic distribution of tensile forces in the soil nails are shown in Figure 2.

The air in the hole was exhausted from the outgoing grouting pipe while filling the hole with cement slurry from the ingoing grouting pipe. Their test results showed that the characteristics of pullout shear stress versus pullout displacement were highly associated with the soil degree of saturation and the soil nail pullout resistance in the saturated condition was the lower comparing to those in the unsaturated conditions.

The soil nail pullout failure can be simulated in a progressive failure way cc637 the present model.

PUB C Soil nailing – best practice guidance, CIRIA – Publication Index | NBS

The results of the projects lead to the development of the French method for the design of soil nails. As mentioned in Section 4.

It is noted that the soil properties have changed during the previous tests, hence basic property tests and triaxial tests for saturated soil has been carried out to determine the soil properties and shear strength. The pullout resistance was as high as kPa, and the water content measured after pullout, was relatively low, as shown in Figure 5. A simple mathematical model for the interaction analysis of a soil nail and the surrounding soil has been developed.

The soil cohesion is zero, and the friction angle is The locations of the PPTs are shown in Figure 4. The divergence of the earth pressures is greater when the pullout displacement is large and failure happens in the soil around the soil nail. In this chapter, the development of a rational simple mathematical model for the complex load transfer mechanism at the interface between soil nail and the surrounding soil is presented. The major forces are axial tension, with bending moments and shear forces being of secondary importance.

After placing the flexible plastic film, the drilling machine was placed and fixed on the ground Figure 4.

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