Discrete Element Analysis of the Strength Anisotropy of Fiber-Reinforced Sands Subjected to Direct Shear Load

Round 1

Reviewer 1 Report

Comments on applsci-807984

 

Discrete element analysis of the strength anisotropy of fibre-reinforced sands subjected to direct shear load

GENERAL

The authors use a discrete element method to provide an insight understanding of the influence of the fibre orientation in the shear strength of fibre reinforced soils, material of frequent use in geotechnical applications. The method uses a commercial software based on soft contact approach between rigid bodies defined by contact force laws and allowing overlapping effects. The method consistency has been previously reported using direct shear tests with sands and fibre reinforced sands, assuming a random distribution of the polypropylene fibre orientations within the soil matrix. Four different mechanisms are considered in the method to simulate the interaction between particles (fibres and sand grains) by means of three different models. The method set up allows the authors to consider individual fibre orientations and obtain the fibre orientation that provides optimum shear test results. In short, their contribution is a consistent explanation on how the fibres with different orientations behave in the direct shear tests of fibre reinforced sand soils.

The text is correctly and clearly organised, and language is quite correct and easy to read.

 

Introduction

In line 30, the authors show 26 references, some of them not relevant for the paper and some quite old. It is suggested to only include those relevant for the paper and connect them with it.

Conversely in the follwing lines a reference is missing:

• Line 25, after reproductibility
• Line 33, after fibres
• Line 41, after “analysis
• Line 44, after compacted

 

DEM simulation of direct shear test

Figure 2b is not mentioned in the text.

In lines 75-82 the wording about the modeling of the fibras. It is mentioned that they can take several shapes considering only straigth fibres. Was the stiffnes of the fibres considered in the simulation? Polypropylene fibres (line 199) migh vary in shape during the tests.

 

Line 86, please indicate the reference where the laboratory test results are shown.

Lines 95-100, the test speed would enhance the explanation

In lines 104 (period, upper case)

In lines 199-202 include fibre diamter and slenderness

Results and discussion

It would be of interest to include simulations with inclined fibres 120º and 150º

Line 215 says direct shear tests. This expression might be confuse the meaning with laboratory tests.

Lines 258 and 271 please impersonal style

In line 261, is this about Figure 9?

In line 366, this seems adequate for polymer fibres, how about steel fibres?

Conclusions

Line 410 y 411 says that fibres are more efficiente placed at 90º, are you sure? In what terms? Displacement, energy, etc.

 

Author Response

Please see the attachment.

Author Response File: Author Response.doc

Reviewer 2 Report

The article presents interesting aspects of artificial soil reinforcement in order to improve the strength features of the ground. However, It would be interesting to include some information about the material of this reinforcement and its influence on the natural environment. The history clearly shows that artificial improvements made by humans are not very clever in terms of long-time consumption of natural resources.

The potential field of application of such an improved ground may be mentioned.

From technical and typesetting side I have only one remark - Eq(6) - it would be more readable if the indexes 1 and 2 were placed below or placed in brackets, not up - in 'up' case it seems to be the power of m value.

 

Author Response

Please see the attachment.

Author Response File: Author Response.doc