Determination of Collapse Potential of Gypseous Soil from Field and Laboratory Tests

Matlan

Advances in Civil Engineering

et al. 2021

The focus of this study was to investigate the effect of loess soil treated with lime on the lateral-seepage response. Three groups of box experiments were carried out to study the lateral-seepage effect under different types of loess-lime structures. Automated testing systems were designed to perform experiments and collect data. Additionally, numerical analysis of lateral-seepage impact and embankment settlement was performed. Finally, moisture content and settlement were monitored to quantify lateral-seepage effect results under corresponding loess-lime treatment. Results showed that loess-lime compaction piles and diaphragm wall structures could effectively prevent lateral seepage, and the latter was better. The simulated results are similar to the measured values of the box experiment, which indicates the accuracy of the simulation analysis and further supports the experimental results of this study.

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Analysis Study on Loess‐Lime Structures Used for Lateral Antiseepage in Deep Collapsible Ground Embankment

Matlan

Advances in Civil Engineering

et al. 2021

“…The collapsibility is one of the most important characteristics of gypseous soils. There are many methods to determine the soil collapsibility; the most important and the most widely used is "one-dimensional oedometer test", which includes two methods [18]: 1-"Single Oedometer Test, (SOT)", An examination proposed by "Knight" in 1963. In this research this test is adopted, this test is conducted by using the oedometer apparatus.…”

Section: Collapsibility Testmentioning

confidence: 99%

Influence of Iron Furnaces Slag on Collapsibility and Shear Strength of Gypseous Soil

Abbas

Al-Luhaibi

2020

Tikrit j. eng. sci.

Gypseous soil is one of the soils that suffer from problems and suffers from a reduction of shear strength and collapse when exposed to water immersion or water filtration in it. Many researchers have tried to solve these problems in different ways and by using many materials as additives to improve the performance and efficiency of this soil. In this research, the behavior of soil with a high content of gypsum (61.49%) is examined, using iron slag which is a by-product of the iron making process in melting furnaces, used as an additive in proportions (2, 4, 6, 8, 10., 12) %, by dry mixing method with soil. Tests are carried out to determine the effect of this substance on the shear strength parameters. The effect of water immersion on soil cohesion (c) is reduced until it reaches (c) in the case of immersion a value very close to the value in the dry state at slag ratio (10) %. This is the optimum ratio of slag to improve the value of (c). Whereas for the value of (ø), with the increase of the slag rate for both wet and dry cases, the value of (ø) increases, where (ø) reaches the highest value at; the slag rate (10) % for the dry state, and the slag rate (8) % for the soaked case. Whereas for the collapse potential (Cp), adding the slag reduces the value of the soil collapse potential (Cp), from (10.6) to the soil without additives until (0.95) for the slag rate (12) %. Then the soil becomes problematic soil.

“…However, the degree of such disturbance of each method remains unclear, especially when being used in loess-paleosol sequence that is water sensitive (Fattah et al, 2017;Hayal et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Influence of Drilling Methods on the Results of Standard Penetration Test in Loess–Paleosol Sequence

et al. 2022

Front. Built Environ.

Standard penetration test (SPT) is an important in situ measurement for field investigation of geotechnical and geological engineering. The drilling approaches for implementation of SPT can be classified into dry, wet, and water circulation drillings according to the amount of water used during drilling process. However, the influences of these drilling methods on the SPT results remain unclear, especially when being used in loess–paleosol sequence that is water sensitive. In this study, SPT tests were conducted in a typical loess stratum in the Loess Plateau of China. The difference of SPT N values under the above three drilling methods was compared together with the analysis of characteristics of samples from SPT sampler. The results showed that the N value exhibits positive correlation with dry density of the soil and negative correlation with moisture content. In shallow soil, the average N value under water circulation drilling was slightly higher than that of dry and wet drilling. This is because that the residual soil at the bottom of the drillhole caused by water circulation drilling provides additional penetration resistance. In deep soil, the difference of average N values among all three drilling methods was minimal although the structure of the samples from the SPT sampler differs from one another, indicating the determination of soil density on the SPT result. Empirical equations were proposed for the estimation of unconfined compressive strength of loess–paleosol sequence on the basis of SPT N values under the three drilling methods. Considering the efficiency of drilling and stability of SPT results, it is suggested that wet drilling is the most applicable method for implementation of SPT in the field investigation of loess–paleosol sequence.