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The bidirectional long short-term memory (Bi-LSTM) network is an innovative computation paradigm that learns bidirectional long-term dependencies between time steps and sequence data to predict future occurrences. This study proposes a framework to incorporate Bi-LSTM and data sequencing to predict diameter of jet grouted columns in soft soil in real time. The models are tested using a case study of jet grouting treatment of soft soil. The results show that the proposed strategies can efficiently predict the variation in column diameter with the depth. A comparative performance analysis among the Bi-LSTM, original long short-term memory (LSTM) and support vector regression (SVR) approaches is also conducted. The Bi-LSTM performs better than both the LSTM and SVR in root-mean-square error. This result substantiates the efficacy of modeling sequential step-by-step jet grouting process using the Bi-LSTM. Based on the analyzed results, some recommendations for improving the current design of jet grout columns are proposed.

Wastewater treatment plants (WWTPs) rarely eliminate emerging contaminants from effluents they discharged into waterways, and therefore, represent significant contaminations sources with deleterious environmental risks. This paper presents a VIKOR-based model to assess the contamination risk posed by a cluster of WWTPs. A risk index was defined via building a membership function embodying the performance degrees of WWTPs and risks levels within the framework of fuzzy set theory. The proposed approach was tested using a case study of WWTPs cluster along the Pearl River. Sensitivity analyses were carried out to investigate the robustness of the model. The results confirmed the ability of the proposed approach to reveal the risk level of a given treatment point. Further, the comparison with a TOPSIS scheme as well as sensitivity analysis results substantiate the consistency, accuracy, and reliability of the proposed approach. It is therefore bounds to improve the decentralized management of WWTPs-induced river contamination.

This paper proposes an improved soil-water-structure coupled interaction model within the framework of smoothed particle hydrodynamics (SPH). The continuous penetration process of the spudcan in clayey soil was investigated along with the concomitant variation of pore water pressure. The proposed method enables the efficient capturing of excess pore water pressure variation in soil undergoing large deformations. Verification and validation performed using previous numerical investigations and centrifuge test data indicate that the proposed model is valid, robust, and effective. This model can be employed to solve various penetration problems and other problems involving complex soil-water-structure interaction and large soil deformations.

The data presented in this paper pertain to case records of liquefaction potential surveys in earthquake prone areas. Field performances of 219 sites obtained from various regions (U.S.A, Japan, Turkey, China, Canada, etc …) are put on display. Specifically, this database consists of 253 cone penetration test (CPT) field records, among which 72 cases that did not liquefied and 181 cases that liquefied. In total, 10 principal variables are tabulated including the earthquake magnitude, maximum ground surface acceleration, depth, water depth, total overburden stress, effective overburden stress, Cone Penetration Test (CPT) tip resistance, CPT friction ratio, fines content, shear stress ratio. These data were arbitrarily split into a testing set of 53 cases and a training set of 200 cases. These field observations are compared to prediction values of liquefaction potential assessed using the evolutionary neural network proposed for “Evaluation of soil liquefaction with AI technology incorporating a coupled ENN/t-SNE model” [1]. Keywords: Liquefaction, Database, CPT, Neural network

A huge gas explosion occurred on 13 June 2021 in Shiyan City, China, resulting in 25 casualties and serious injuries to 37 people. The main victims of this explosion were stall keepers and customers buying breakfast and fresh vegetables in the food market. There is a continuous need to enhance the understanding of such unfortunate events, given the dangers they pose. This study analyzes the causes of this accident considering the general background and scenes of the explosion, and then describes the rescue operations undertaken. The investigation results revealed that the explosion was caused by the poor maintenance of gas facilities and negligence of safety regulations. It is, therefore, recommended that the control of these two main aspects be strengthened to reduce the recurrence of such unfortunate accidents.

This paper discusses recent advances in the implementation of horizontal jet grouting (HJG) for the ground improvement of soft soil. Field trials of HJG were undertaken in soft soils in Shanghai, and the research is reported and discussed in this paper. Particular emphasis was placed to study the hardening process in non-cohesive soils. The recent innovations in HJG were found to arise principally from challenges in implementing jet grouting in sandy soil and also from the harmful effects on the surrounding caused by the traditional implementation process. Accordingly, the recently developed composite jet pipe, pressure-control jet grouting and control discharge horizontal jet grouting methods have been successfully implemented to mitigate the ground upheaval and displacements. Moreover, the characteristics of the jet grout columns obtained with these methods were found as a rule to perform beyond expectations. It was also found that the newly developed horizontal twin-jet grouting technology, underpinned by an instant-solidification mechanism, overcame challenging issues such as mixing uniformity, loss of admixture and hardening. The characteristics of hardening in particular have initiated new perspectives, given that a better acquaintance of the mechanisms of hardening and ground displacements is bound to play an important role in the future practice and the development of the jet grouting process. Interestingly, smoothed particle hydrodynamics technique was found to be suited for modeling jet grouting mechanisms.

This paper presents a comprehensive review on subsea jet trenching technology via a critical analysis of its principle, mechanism, devices, modeling approaches, as well as properties of subsea sediments. This review shows that the success of jet trenching operations is closely related to some key factors including the soil conditions, trencher specifications, and characteristics of pipelines or cables. Three case histories are presented to demonstrate the importance of these key factors and their interrelationships. This paper also points out a number of challenges pertaining to the implementation of the jet trenching method in carbonate sediments, as well as some limitations and gaps in the existing modeling approaches. Future perspective researches that are recommended to develop: (1) promising theories, like turbulent submerged flow, and (2) robust numerical approaches, such as the smoothed particle hydrodynamics (SPH) and material point method (MPM) to substantiate the experimental experience and reveal possible hidden mechanisms.

This paper presents a new evolutionary neural network (ENN) algorithm coupled with the dimensionality reduction technique ‘t-distributed stochastic neighbour embedding’ (t-SNE). The ENN model features the crossbreeding of a differential evolution method and a stochastic gradient optimisation algorithm. The t-SNE is used to visualise the training and testing datasets and the ENN model performance. The proposed ENN model is applied to a relatively large soil liquefaction database. The good convergence and generalisation ability of the proposed model and the negligible misclassification results demonstrate that the proposed ENN model can provide accurate, efficient, and flexible results. The prominent and practical abilities of t-SNE to recover the structure of the initial conditions and to demonstrate the ENN model performance are discussed. This coupled approach simplifies the analysis and/or prediction of hazards for which large quantities of data are required.

The few methodologies available for estimating the displacement induced by the action of a fluid jet on the soil are almost all based on the cavity expansion theory, which the adaptiveness to model this phenomenon can be questioned due to some significant drawbacks. This paper investigates the suitability of the SPH approach to investigate the ground displacement induced by jet grouting. A simulation of a water jet impinging on a soil mass is performed using AUTODYN-2D. In this simulation, the soil is modelled as a granular elastoplastic material, whereas the water is assumed to perform as a Newtonian fluid. The interaction between these two bodies is therefore investigated in order to demonstrate the advantage of the SPH method over others. In particular, the strain and pressure variations in the soil are exploited to clearly expose the limitations of the cavity expansion based approaches. It is apparent that the SPH approach simulates the fluid-soil interaction more realistically and thus can be used to investigate the aforementioned mechanism. The results also highlight some computation instabilities that occurred during the simulation. It is therefore recommended to adopt coding as solving technique, notably to have a greater flexibility in dealing with issues of this type.

The jet grouting technique was originally initiated in the UK and progressively developed following the needs for larger geometries, ease of implementation, economic rationality, and better mechanical properties. This paper presents a comprehensive review of the development and practice of jet grouting through some fundamental concepts and relevant case studies. Subsequently, a laboratory testing program is performed to investigate the factors affecting the efficacy of the twin grouting system. The principal objective of this study is to define the suitable conditions for the jet grouting efficacy regarding economic rationality as well as quality control. For the first phase, a particular emphasis is placed on the properties of jet columns, site geological conditions, implementation methods, and the justification of each selected treatment option, while the second phase mainly focuses on the unconfined compressive strength (UCS) tests. It follows that the mono-fluid jet grouting system presents a valuable flexibility in dealing with complex configurations; yet, the double- and triple-fluid systems are more indicated for cases of mass treatments for which large portions of space must be treated and overlapping is fundamentally important for the reliability of the treatment. Furthermore, it was established that the efficacy of the twin-jet method primarily relies on the proper adequacy of some critical parameters, namely, the cement content, the water-cement ratio, and cement slurry-water glass ratio. In spite of some uncertainties inherently related to the technique, the UCS test represents the quintessential laboratory index for evaluating the mechanical properties of grouted elements, deriving jet grouting efficacy and the economics of jet grouts.