The study investigates the effectiveness of bamboo grids as a reinforcement material in filled loess embankments located in high and steep gullies. It explores how bamboo grids can replace traditional geogrids, focusing on their impact on shear strength and differential settlement. The research includes large-scale direct shear tests, numerical simulations, and field measurements to analyze the interface reinforcement effect. Findings indicate that bamboo grids significantly enhance shear strength and reduce differential settlement, making them a viable option for infrastructure projects in loess regions. This study is essential for civil engineering professionals and researchers interested in sustainable construction materials.

Key Points

  • Investigates bamboo grid reinforcement in loess embankments
  • Includes large-scale direct shear tests and numerical simulations
  • Demonstrates significant reduction in differential settlement
  • Compares bamboo grids to traditional geogrids
  • Focuses on infrastructure projects in high and steep gullies
Dhruva Patel
Author:Guozhou Chen, Haodong Tian, Zibo Du, Jingwei Zhang, Yuancheng Guo, Julong Wang
20 pages
Language:English
Type:Research Paper
Engineering
Dhruva Patel
Author:Guozhou Chen, Haodong Tian, Zibo Du, Jingwei Zhang, Yuancheng Guo, Julong Wang
20 pages
Language:English
Type:Research Paper
Engineering
Dhruva Patel
Author:Guozhou Chen, Haodong Tian, Zibo Du, Jingwei Zhang, Yuancheng Guo, Julong Wang
20 pages
Language:English
Type:Research Paper
Engineering
265

Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully pdf

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Citation: Chen, G.; Tian, H.; Du, Z.;
Zhang, J.; Guo, Y.; Wang, J. Study on
the Interface Reinforcement Effect of
Bamboo Grid in Filled Loess
Embankment in a High and Steep
Gully. Buildings 2024, 14, 3423.
https://doi.org/10.3390/
buildings14113423
Academic Editors: Bjorn Birgisson
and Antonio Caggiano
Received: 19 September 2024
Revised: 4 October 2024
Accepted: 14 October 2024
Published: 28 October 2024
Copyright: © 2024 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
buildings
Article
Study on the Interface Reinforcement Effect of Bamboo Grid in
Filled Loess Embankment in a High and Steep Gully
Guozhou Chen
1,2,3
, Haodong Tian
1,
*, Zibo Du
1
, Jingwei Zhang
1
, Yuancheng Guo
1
and Julong Wang
1
1
School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China; cgzsxmz@163.com (G.C.);
duzibo@zzu.edu.cn (Z.D.); zhangjw1998@163.com (J.Z.); guoyuancheng@163.com (Y.G.);
t215801@163.com (J.W.)
2
Huanghe S & T University, Zhengzhou 450006, China
3
Henan Urban Planning and Design Institute Co., Ltd., Zhengzhou 450044, China
* Correspondence: tianhd@gs.zzu.edu.cn
Abstract: A bamboo grid is a new type of reinforcement material, which can replace traditional
geogrids in the reinforcement of embankments. In this study, the reinforcement effect of the bamboo
grid that is only set at the interface between the filled and undisturbed soils of the filled loess
embankment in a high and steep gully was investigated. The influence of reinforcement position
and grid spacing on the reinforcement effect was studied by carrying out a large-scale direct shear
test, numerical simulation, and field measurement. The results indicated that the bamboo grid
could enhance the shear strength of the reinforcement interface. The interface shear strength first
improved and then decreased with the decrease in grid spacing. The differential settlement was
significantly reduced after the reinforcement of the bamboo grid at the interface. Compared with
other reinforcement positions, setting the bamboo grid in the upper part of the embankment was the
most efficient and economical. When the grid spacing became dense, the reinforcement effect was
improved as the differential settlement decreased. However, the improvement in the reinforcement
effect by decreasing the grid spacing was limited, which meant there was an optimal grid spacing.
Keywords: bamboo grid; interface reinforcement; filled loess embankment; differential settlement;
numerical simulation
1. Introduction
Loess is widespread in Northwest China, with a range of over 631,000 km
2
, accounting
for 6.6% of the total area of the country [
1
]. With the rapid development of West China, a
large number of transportation infrastructure projects have been constructed in the loess
gully region. Similar to the embankment widening project [
2
–
5
], there usually exists
differential settlement at the interface between the filled and undisturbed soils for the filled
loess embankment in high and steep gullies. Excessive differential settlement would cause
various embankment and pavement diseases. The conventional method uses geosynthetics,
i.e., geogrids, to restrain the differential settlement of the embankment [
6
–
9
]. However,
a geogrid does not have bending capacity. It is not suitable for treating large differential
settlement of the embankment [10].
Bamboo has proven to be a good reinforcement material due to its excellent mechanical
properties [
11
,
12
] including flexural properties [
13
], easy availability, and green character-
istics [
14
]. Compared to the geogrid, the tensile strength of bamboo is nine times higher.
Although the tensile strength value of bamboo is reduced to some degree after chemical
treatment to increase durability, it is still higher than that of geosynthetics [
15
]. It can satisfy
the specification requirement for reinforcing the embankment of a highway and replace
the geogrid [
16
,
17
]. Compared to the high cost of geosynthetics [
18
], bamboo is cheaper
as well. Extensive studies have been performed on the reinforcement technology with
bamboo grid. As a kind of reinforcement material, a bamboo grid can significantly reduce
Buildings 2024, 14, 3423. https://doi.org/10.3390/buildings14113423 https://www.mdpi.com/journal/buildings
Buildings 2024, 14, 3423
2 of 20
the compressibility of soil [
19
] and the settlement of the embankment [
20
–
22
], as well as
improve the bearing capacity of soil [
23
]. It was also employed to enhance slope stability,
which showed that the bamboo grid was able to resist the applied loads and maintain the
stability of the slope [
24
,
25
]. In terms of differential settlement treatment, Luo et al. [
26
]
compared the performance of the bamboo grid and geogrid set at the widening interface of
the embankment. The results showed that, after being reinforced with the bamboo grid
in the new fill, differential settlement on top of the embankment was effectively reduced,
and its reinforcement effect was better than that of the geogrid. To sum up, due to better
mechanical properties and reinforcement performance than traditional geogrids, bamboo
grids can be used to constrain the differential settlement of the filled loess embankment in
a high and steep gully.
Generally, to restrain the differential settlement of the widening embankment, rein-
forcement materials are used in three ways. The first is to set reinforcement materials only
in the new fill [
27
,
28
]. The second is to set reinforcement materials in the new fill and the
interface [
29
]. The final way is to set reinforcement materials both in the new fill and the
existing soil [
30
]. Similarly, to restrain the differential settlement of the filled embankment
in a high and steep gully, there will be several reinforcement schemes as well. This paper
only focuses on the scheme of setting reinforcement materials at the interface, as shown in
Figure 1.
Buildings 2024, 14, x FOR PEER REVIEW 2 of 21
technology with bamboo grid. As a kind of reinforcement material, a bamboo grid can
significantly reduce the compressibility of soil [19] and the settlement of the embankment
[20–22], as well as improve the bearing capacity of soil [23]. It was also employed to en-
hance slope stability, which showed that the bamboo grid was able to resist the applied
loads and maintain the stability of the slope [24,25]. In terms of differential settlement
treatment, Luo et al. [26] compared the performance of the bamboo grid and geogrid set
at the widening interface of the embankment. The results showed that, after being rein-
forced with the bamboo grid in the new fill, differential settlement on top of the embank-
ment was effectively reduced, and its reinforcement effect was better than that of the ge-
ogrid. To sum up, due to better mechanical properties and reinforcement performance
than traditional geogrids, bamboo grids can be used to constrain the differential settle-
ment of the filled loess embankment in a high and steep gully.
Generally, to restrain the differential settlement of the widening embankment, rein-
forcement materials are used in three ways. The first is to set reinforcement materials only
in the new fill [27,28]. The second is to set reinforcement materials in the new fill and the
interface [29]. The final way is to set reinforcement materials both in the new fill and the
existing soil [30]. Similarly, to restrain the differential settlement of the filled embankment
in a high and steep gully, there will be several reinforcement schemes as well. This paper
only focuses on the scheme of setting reinforcement materials at the interface, as shown
in Figure 1.
However, the interface reinforcement technology with bamboo grids has rarely been
studied. Therefore, it is necessary to study the reinforcement effect of the bamboo grid set
at the interface and its influencing factors. In this study, a large-scale direct shear test was
conducted to analyze the shear characteristics of the interface between the reinforcement
materials and the reinforced soil. A settlement measurement of a practical engineering
case was conducted to study the settlement law of the filled loess embankment. By using
ABAQUS 2022 software, a numerical simulation was carried out, and the interface rein-
forcement effect of the bamboo grid and its influential factors including reinforcement
position and grid spacing were analyzed.
Figure 1. Scheme of reinforcement materials only set at the interface.
2. Large-Scale Direct Shear Test
Interface characteristics between the bamboo grid and the reinforced soil have a sig-
nificant influence on the reinforcement effect of the bamboo grid. To study the interface
characteristics, large-scale direct shear tests with different reinforcement types and grid
spacings were conducted.
2.1. Test Materials
Moso bamboo aged 5 to 6 years old was selected for tests. The chest-height diameter
of these 5- to 6-year-old bamboos was more than 50 mm. The wall thickness was 2–3 mm.
The bamboo was processed into strips. The width of these strips was 20 mm. In practical
engineering cases which need long-term anticorrosion, bamboo is soaked in boric acid
Figure 1. Scheme of reinforcement materials only set at the interface.
However, the interface reinforcement technology with bamboo grids has rarely been
studied. Therefore, it is necessary to study the reinforcement effect of the bamboo grid set
at the interface and its influencing factors. In this study, a large-scale direct shear test was
conducted to analyze the shear characteristics of the interface between the reinforcement
materials and the reinforced soil. A settlement measurement of a practical engineering
case was conducted to study the settlement law of the filled loess embankment. By us-
ing ABAQUS 2022 software, a numerical simulation was carried out, and the interface
reinforcement effect of the bamboo grid and its influential factors including reinforcement
position and grid spacing were analyzed.
2. Large-Scale Direct Shear Test
Interface characteristics between the bamboo grid and the reinforced soil have a
significant influence on the reinforcement effect of the bamboo grid. To study the interface
characteristics, large-scale direct shear tests with different reinforcement types and grid
spacings were conducted.
2.1. Test Materials
Moso bamboo aged 5 to 6 years old was selected for tests. The chest-height diameter
of these 5- to 6-year-old bamboos was more than 50 mm. The wall thickness was 2–3 mm.
The bamboo was processed into strips. The width of these strips was 20 mm. In practical
engineering cases which need long-term anticorrosion, bamboo is soaked in boric acid
solution for 24 h first to prevent fungi, bacteria, and ants from proliferating inside the
bamboo. Then, asphalt paint is applied on the surface of the bamboo to prevent external
Buildings 2024, 14, 3423
3 of 20
water from entering the bamboo, as well as to prevent boric acid loss. These processes do
not have a significant influence on the properties of bamboo. In this study, the direct shear
test was fast. Therefore, only asphalt paint was used for the anticorrosion of bamboo strips.
The bamboo strips were fixed at the intersections by 4 mm diameter steel wire. Thus, the
bamboo grids were formed, as shown in Figure 2. For better comparison, a geogrid was
also used. The biaxial geogrid (TGSG2020) used in the tests was made of polypropylene,
and the mesh size was 50 mm × 50 mm, as shown in Figure 3.
Buildings 2024, 14, x FOR PEER REVIEW 3 of 21
solution for 24 h first to prevent fungi, bacteria, and ants from proliferating inside the
bamboo. Then, asphalt paint is applied on the surface of the bamboo to prevent external
water from entering the bamboo, as well as to prevent boric acid loss. These processes do
not have a significant influence on the properties of bamboo. In this study, the direct shear
test was fast. Therefore, only asphalt paint was used for the anticorrosion of bamboo
strips. The bamboo strips were fixed at the intersections by 4 mm diameter steel wire.
Thus, the bamboo grids were formed, as shown in Figure 2. For better comparison, a ge-
ogrid was also used. The biaxial geogrid (TGSG2020) used in the tests was made of poly-
propylene, and the mesh size was 50 mm × 50 mm, as shown in Figure 3.
The loess used was obtained from a section of the National Highway of China. It was
completely renewed Quaternary soil with a color of brown-yellow. The basic mechanical
properties tests of the soil were conducted according to ASTM D698 and ASTM D4318.
The results are shown in Table 1.
Figure 2. Bamboo grid.
Figure 3. Geogrid.
Table 1. Basic mechanical properties of the test soil.
Material Density (g·cm
−3
)
Optimum
Moisture (%)
Maximum Dry
Density (g·cm
−3
)
Liquid Limit
(%)
Plastic Limit
(%)
Plasticity Index
Loess 1.62 11.94 1.95 25.1 17 8.1
2.2. Test Program
The test employed a large-scale direct shear apparatus that was designed and devel-
oped by Zhengzhou University, as shown in Figure 4. The size of the upper shear box was
500 mm × 500 mm × 150 mm, and the lower shear box was 650 mm × 500 mm × 150 mm.
According to the standard for direct shear tests (ASTM D5321/D5321M-14), the test
procedures were as follows. The soil was first air-dried and then mixed with its optimum
Figure 2. Bamboo grid.
Buildings 2024, 14, x FOR PEER REVIEW 3 of 21
solution for 24 h first to prevent fungi, bacteria, and ants from proliferating inside the
bamboo. Then, asphalt paint is applied on the surface of the bamboo to prevent external
water from entering the bamboo, as well as to prevent boric acid loss. These processes do
not have a significant influence on the properties of bamboo. In this study, the direct shear
test was fast. Therefore, only asphalt paint was used for the anticorrosion of bamboo
strips. The bamboo strips were fixed at the intersections by 4 mm diameter steel wire.
Thus, the bamboo grids were formed, as shown in Figure 2. For better comparison, a ge-
ogrid was also used. The biaxial geogrid (TGSG2020) used in the tests was made of poly-
propylene, and the mesh size was 50 mm × 50 mm, as shown in Figure 3.
The loess used was obtained from a section of the National Highway of China. It was
completely renewed Quaternary soil with a color of brown-yellow. The basic mechanical
properties tests of the soil were conducted according to ASTM D698 and ASTM D4318.
The results are shown in Table 1.
Figure 2. Bamboo grid.
Figure 3. Geogrid.
Table 1. Basic mechanical properties of the test soil.
Material Density (g·cm
−3
)
Optimum
Moisture (%)
Maximum Dry
Density (g·cm
−3
)
Liquid Limit
(%)
Plastic Limit
(%)
Plasticity Index
Loess 1.62 11.94 1.95 25.1 17 8.1
2.2. Test Program
The test employed a large-scale direct shear apparatus that was designed and devel-
oped by Zhengzhou University, as shown in Figure 4. The size of the upper shear box was
500 mm × 500 mm × 150 mm, and the lower shear box was 650 mm × 500 mm × 150 mm.
According to the standard for direct shear tests (ASTM D5321/D5321M-14), the test
procedures were as follows. The soil was first air-dried and then mixed with its optimum
Figure 3. Geogrid.
The loess used was obtained from a section of the National Highway of China. It was
completely renewed Quaternary soil with a color of brown-yellow. The basic mechanical
properties tests of the soil were conducted according to ASTM D698 and ASTM D4318. The
results are shown in Table 1.
Table 1. Basic mechanical properties of the test soil.
Material
Density
(g·cm
−3
)
Optimum
Moisture (%)
Maximum Dry
Density
(g·cm
−3
)
Liquid
Limit
(%)
Plastic
Limit
(%)
Plasticity
Index
Loess 1.62 11.94 1.95 25.1 17 8.1
2.2. Test Program
The test employed a large-scale direct shear apparatus that was designed and devel-
oped by Zhengzhou University, as shown in Figure 4. The size of the upper shear box was
500 mm
×
500 mm
×
150 mm, and the lower shear box was 650 mm
×
500 mm
×
150 mm.
/ 20
End of Document
265

Figures

Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 1
Bamboo grid.
Geogrid.
Bamboo grid.
Geogrid.
Large-scale direct shear apparatus: (
Large-scale direct shear apparatus: (
Large-scale direct shear apparatus: (
Diagrammatic sketch of the direct shear test.
Large-scale direct shear apparatus: (
Diagrammatic sketch of the direct shear test.
Diagrammatic sketch of the direct shear test.
Diagrammatic sketch of the direct shear test.
Large-scale direct shear apparatus: (
The reinforced materials laid at the junction: (
The reinforced materials laid at the junction: (
Diagrammatic sketch of the direct shear test.
Bamboo grid with di
Stress diagram of soil particles in the shear process: (
Stress diagram of soil particles in the shear process: (
Stress diagram of soil particles on the surface of reinforced materials with di
Stress diagram of soil particles on the surface of reinforced materials with di
Interface reinforced with bamboo grid.
) Embankment section 3.
Location of the measuring points: (
Buildings
Location of the measuring points: (
Three-dimensional model of filled embankment in high and steep gully.
The cross-section of the
Top view of the terrain.
Three-dimensional model of
The cross-section of the fill.
Top view of the terrain.
Three-dimensional model of
The cross-section of the fill.
Top view of the terrain.
Boundary conditions of the model.
Mesh of the bamboo grid.
Mesh of the bamboo grid.
Cloud chart of the cumulative se
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 22
Cloud chart of the cumulative se
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 22
Cloud chart of the cumulative se
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 22
Reinforcement scheme.
Simpli
Reinforcement scheme.
Simpli
Reinforcement scheme.
Simpli
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 29
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 30
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 31
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 29
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 30
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 31
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 29
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 30
Study on the Interface Reinforcement Effect of Bamboo Grid in Filled Loess Embankment in a High and Steep Gully — Figure 31

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FAQs

What is the main focus of the study on bamboo grid reinforcement?
The study investigates the interface reinforcement effect of bamboo grids in filled loess embankments, specifically in high and steep gullies. It examines how the position of the bamboo grid and the spacing between grids influence the reinforcement effect at the interface between filled and undisturbed soils. The research aims to demonstrate that bamboo grids can effectively enhance shear strength and reduce differential settlement in embankments.
How does bamboo grid compare to traditional geogrids in embankment reinforcement?
Bamboo grids have been shown to possess superior mechanical properties compared to traditional geogrids, including a tensile strength that is nine times higher. This study indicates that bamboo grids not only reduce compressibility and settlement of soil but also improve the bearing capacity of the embankment. The results suggest that bamboo grids are more effective in treating differential settlement than geogrids, particularly when positioned at the interface of the embankment.
What methods were used to analyze the reinforcement effect of bamboo grids?
The study utilized a combination of large-scale direct shear tests, numerical simulations, and field measurements to analyze the reinforcement effect of bamboo grids. The direct shear tests were conducted to assess the interface characteristics between the bamboo grid and reinforced soil, while numerical simulations were performed using Abaqus 2022 software to evaluate the influence of grid spacing and reinforcement position on the overall effectiveness.
What were the findings regarding grid spacing and its impact on reinforcement?
The findings revealed that the shear strength at the interface improved initially with decreasing grid spacing, but eventually decreased after reaching an optimal spacing. The study concluded that while denser grid spacing enhances the reinforcement effect and reduces differential settlement, there is a limit to the improvement, indicating the existence of an optimal grid spacing for effective reinforcement.
What type of bamboo was used in the study and how was it treated?
The study used Moso bamboo aged 5 to 6 years, selected for its appropriate mechanical properties. The bamboo was processed into strips with a width of 20 mm and treated for long-term durability by soaking in a boric acid solution to prevent biological degradation. Additionally, asphalt paint was applied to the surface to protect against moisture ingress and to maintain the integrity of the bamboo.
What are the implications of using bamboo grids in civil engineering projects?
The use of bamboo grids in civil engineering projects, particularly in loess regions, presents a sustainable and cost-effective alternative to traditional geogrids. Given their superior mechanical properties and effectiveness in reducing differential settlement, bamboo grids can enhance the stability and longevity of embankments, thereby addressing common issues associated with infrastructure in steep gully areas.

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