It was 35 years ago since the first usage of Artificial Intelligence (AI) technique in geotechnical engineering, during those years many (AI) techniques were developed based in mathematical, statistical and logical concepts, but the breakthrough occurs by mimicking the natural searching and optimization algorithms. This huge development in (AI) techniques reflected on the geotechnical engineering problems. In this research, 626 paper and thesis published in the period from 1984 to 2019 concerned in applying (AI) techniques in geotechnical engineering were collected, filtered, arranged and classified with respect to subject, (AI) technique, publisher and publishing date and stored in a database. The extracted information from the database were tabulated, presented graphically and commented. The main conclusions is that the number of researches in this field increases almost exponentially, the most used (AI) technique is the Artificial Neural Networks and its enhancements where it is presents about half the researches and finally correlating soil and rock properties is the most addressed subject with about 30% of the researches.

35 Years of (AI) in Geotechnical Engineering: State of the Art

The process of removing sediments from the bottom of dams generates large amounts of dredged sediments, which are considered waste. The purpose of this research was to present the results of testing conducted on dredged sediment stabilized with ordinary Portland cement (OPC) and fly ash (FA) for reuse as pavement materials. The base sediment was high plasticity silt (MH) based on the Unified Soil Classification System (USCS). The experiments in this study consisted of unconfined compression (UC), California bearing ratio (CBR), and resilient modulus (Mr) tests on stabilized dredged sediment. A combination of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) was used to investigate the microstructures of the stabilized specimens. Finally, a simple comparative cost analysis between roads using conventional earthen materials and stabilized dredged sediment was performed. The results showed that the unconfined compressive strength (qu), CBR, and Mr improved the pavement materials from unsuitable to suitable, and a 10% FA content provided the optimal strength enhancement. The SEM images showed that the calcium silicate hydrate (CSH) product, which was formed by hydration and pozzolanic reactions, attached to the clay clusters and filled the pore spaces between clay particles, resulting in a denser sediment structure. The EDX analyses showed that the calcium weight proportion and the silica-aluminum ratio were important factors in improving the strength of the dredged sediment treated with OPC and FA. These EDX results agreed with the qu, CBR, and Mr results. For the studied situation, roads using stabilized sediment were 1.5 times more economical than roads using conventional earthen pavement materials. Dredged sediments treated with OPC and FA can be sustainably reused as pavement materials based on the Department of Highways of Thailand standard, as well as the recommendations of Austroads (2017). Thus, for suitable sediments, reuse in road and pavement construction may be considered with appropriate treatment and conditioning.

Sustainable reuse of dredged sediments as pavement materials by cement and fly ash stabilization

Safe disposal of coal bottom ash by solidification and stabilization techniques

Similar to other swarm-based algorithms, the recently developed whale optimization algorithm (WOA) has the problems of low accuracy and slow convergence. It is also easy to fall into local optimum. Moreover, WOA and its variants cannot perform well enough in solving high-dimensional optimization problems. This paper puts forward a new improved WOA with joint search mechanisms called JSWOA for solving the above disadvantages. First, the improved algorithm uses tent chaotic map to maintain the diversity of the initial population for global search. Second, a new adaptive inertia weight is given to improve the convergence accuracy and speed, together with jump out from local optimum. Finally, to enhance the quality and diversity of the whale population, as well as increase the probability of obtaining global optimal solution, opposition-based learning mechanism is used to update the individuals of the whale population continuously during each iteration process. The performance of the proposed JSWOA is tested by twenty-three benchmark functions of various types and dimensions. Then, the results are compared with the basic WOA, several variants of WOA and other swarm-based intelligent algorithms. The experimental results show that the proposed JSWOA algorithm with multi-mechanisms is superior to WOA and the other state-of-the-art algorithms in the competition, exhibiting remarkable advantages in the solution accuracy and convergence speed. It is also suitable for dealing with high-dimensional global optimization problems.

A new improved whale optimization algorithm with joint search mechanisms for high-dimensional global optimization problems

Stabilization/solidification and recycling of sediment from Taihu Lake in China: Engineering behavior and environmental impact

Large amount of sediments are dredged from connecting drains of River Yamuna as a part of its regular maintenance in Delhi. These dredged soils generally considered as waste due to its poor engineering properties. In this study attempt has been made to improve strength, durability and immobilize contaminants of the contaminated dredged soil collected from Najafgarh drain by mixing it with different proportion of cement–bottom ash mix so that it can suitably fulfill the requirements of highway subgrade materials. Compaction test, California bearing ratio test, wetting and drying test, toxicity characteristic leaching procedure leachate test and scanning electron microscope test were performed on the contaminated dredged soil specimens and the results indicated that cement–bottom ash mix was effective in improving the engineering properties of the contaminated dredged soils. Also, the test results of the contaminated dredged soil stabilized with cement–bottom ash mix were better in comparison to cement alone. From the study it reveals that the optimum proportion of additive to be used to improve properties of the contaminated dredged soils was 10% cement + 10% bottom ash mix for use it as a highway subgrade fill materials.

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Contaminated dredged soil stabilization using cement and bottom ash for use as highway subgrade fill

The dredging of lakes, rivers, drains or water bodies, etc. is a regular practice all over the world and disposal of these dredged soils is a major problem due to the scarcity of open land in the urban areas. At present for handling this problem, engineers and soil experts are trying to find out alternative solutions such as the use of the dredged soil as constructional material in different development projects. This study deals with the contaminated dredged soil of Najafgarh drain, a major connecting drain of Yamuna river (Delhi) and aims at its use as alternative highway subgrade material after stabilization/solidification with cement, bottom ash and steel slag in different ratios. As the dredged soil contains a certain amount of organic matter that the influence the chemical process of stabilization/solidification, thus thermal treatment of raw dredged soil has also been carried out to ascertain its effects on stabilization/solidification. Furthermore, samples out of all those have satisfied the acceptance criteria of highway subgrade material have been selected, and finally, the most suitable sample out of them has been decided along with the assessment of its degree of suitability to use as highway subgrade materials. For both cases, the concept of the fuzzy logic of Prof. Latfi Zadeh has been introduced.

http://www.jsoftcivil.com/article_82750_866447e60a621861938b487641d38051.pdf

V. K. Arora

Papers

Contaminated dredged soil stabilization using cement and bottom ash for use as highway subgrade fill

Selection of Most Suitable Stabilized/Solidified Dredged Soil to Use in Highway Subgrade Layer Construction

Ranking of stabilizers to stabilize/solidify dredged soil as highway construction material