Effect of cementation on the small-strain stiffness of granite residual soil

Most previous studies have focused on the small strain stiffness of sedimentary soil while little attention has been given to residual soils with different properties. Most studies also neglected the effects of the deviator stress, which is extensively involved in civil engineering. This note considers the effects of the deviator stress on the small-strain stiffness of natural granite residual soil (GRS) as established from resonant column tests performed under various stress ratios. Although increasing the stress ratio results in a greater maximum shear modulus for both natural and remolded residual soils, remolded soil is more sensitive to changes in the stress ratio, which highlights the effects of soil cementation. The data herein offers new insights to understand the stiffness of residual soil and other weathered geomaterials.

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Influence of Confining Stress on the Small Strain Stiffness of a Residual Soil under K 0 Conditions

PanAm Unsaturated Soils 2017 ◽

10.1061/9780784481707.041 ◽

2018 ◽

Author(s):

C. E. Torres ◽

J. E. Colmenares

Keyword(s):

Small Strain ◽

Residual Soil ◽

Confining Stress ◽

Small Strain Stiffness

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A proposed method to determine in-situ shear modulus and shear strain decay curves in different structured soil

E3S Web of Conferences ◽

10.1051/e3sconf/20199218004 ◽

2019 ◽

Vol 92 ◽

pp. 18004

Author(s):

Ran An ◽

Lingwei Kong ◽

Aiguo Guo ◽

Xianwei Zhang

Keyword(s):

Shear Modulus ◽

Shear Strain ◽

Soft Soil ◽

Soft Rock ◽

High Standard ◽

Small Strain ◽

Residual Soil ◽

Resonant Column Test ◽

Granite Residual Soil

This paper illustrates the application of the self-boring pressuremeter test and the seismic dilatometer test to acquire the in-situ decay curves of stiffness with shear strain level (G-γ decay curves) of three types of structural soil, which are granite residual soil, structural soft soil and expansive soft rock. The proposed approach in combines the functions of SBPT and SDMT to provide the high standard of accuracy for the small-strain stiffness (from SDMT) and the major attenuation stage of stiffness (from SBPT). Using the proposed mathematical model can properly describe the tendency in typical in-situ G-γ decay curves based on the data of tests. To analyse the suitability of the proposed approach, the G-γ curve obtain from the resonant column test of granite residual soil is also employed to compare with the in-situ curves. The shear modulus G obtained from laboratory tests is found to be smaller and the stiffness attenuation rate is found to be faster than the curve of the in-situ test, which reflects the process of sampling, transporting and preparation of soil samples could cause unrecoverable damages in soil.

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Laboratory model test study of the hydrological effect on granite residual soil slopes considering different vegetation types

Scientific Reports ◽

10.1038/s41598-021-94276-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jie Chen ◽

Xue-wen Lei ◽

Han-lin Zhang ◽

Zhi Lin ◽

Hui Wang ◽

...

Keyword(s):

Root System ◽

Heavy Rainfall ◽

Storage Capacity ◽

Water Storage ◽

Laboratory Model ◽

Residual Soil ◽

Vegetation Types ◽

Water Storage Capacity ◽

Granite Residual Soil ◽

Stem Leaf

AbstractThe problems caused by the interaction between slopes and hydrologic environment in traffic civil engineering are very serious in the granite residual soil area of China, especially in Guangdong Province. Against the background of two heavy rainfall events occurring during a short period due to a typhoon making landfall twice or even two typhoons consecutively making landfall, laboratory model tests were carried out on the hydrological effects of the granite residual soil slope considering three vegetation types under artificial rainfall. The variation in slope surface runoff, soil moisture content and rain seepage over time was recorded during the tests. The results indicate that surface vegetation first effectively reduces the splash erosion impact of rainwater on slopes and then influences the slope hydrological effect through rainwater forms adjustment. (1) The exposed slope has weak resistance to two consecutive heavy rains, the degree of slope scouring and soil erosion damage will increase greatly during the second rainfall. (2) The multiple hindrances of the stem leaf of Zoysia japonica plays a leading role in regulating the hydrological effect of slope, the root system has little effect on the permeability and water storage capacity of slope soil, but improves the erosion resistance of it. (3) Both the stem leaf and root system of Nephrolepis cordifolia have important roles on the hydrological effect. The stem leaf can stabilize the infiltration of rainwater, and successfully inhibit the surface runoff under continuous secondary heavy rainfall. The root system significantly enhances the water storage capacity of the slope, and greatly increases the permeability of the slope soil in the second rainfall, which is totally different from that of the exposed and Zoysia japonica slopes. (4) Zoysia is a suitable vegetation species in terms of slope protection because of its comprehensive slope protection effect. Nephrolepis cordifolia should be cautiously planted as slope protection vegetation. Only on slopes with no stability issues should Nephrolepis cordifolia be considered to preserve soil and water.

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