Potential Energy Research Articles

Renewable Energy Potential: Second-Generation Biomass as Feedstock for Bioethanol Production.

Biofuels are clean and renewable energy resources gaining increased attention as a potential replacement for non-renewable petroleum-based fuels. They are derived from biomass that could either be animal-based or belong to any of the three generations of plant biomass (agricultural crops, lignocellulosic materials, or algae). Over 130 studies including experimental research, case studies, literature reviews, and website publications related to bioethanol production were evaluated; different methods and techniques have been tested by scientists and researchers in this field, and the most optimal conditions have been adopted for the generation of biofuels from biomass. This has ultimately led to a subsequent scale-up of procedures and the establishment of pilot, demo, and large-scale plants/biorefineries in some regions of the world. Nevertheless, there are still challenges associated with the production of bioethanol from lignocellulosic biomass, such as recalcitrance of the cell wall, multiple pretreatment steps, prolonged hydrolysis time, degradation product formation, cost, etc., which have impeded the implementation of its large-scale production, which needs to be addressed. This review gives an overview of biomass and bioenergy, the structure and composition of lignocellulosic biomass, biofuel classification, bioethanol as an energy source, bioethanol production processes, different pretreatment and hydrolysis techniques, inhibitory product formation, fermentation strategies/process, the microorganisms used for fermentation, distillation, legislation in support of advanced biofuel, and industrial projects on advanced bioethanol. The ultimate objective is still to find the best conditions and technology possible to sustainably and inexpensively produce a high bioethanol yield.

Analysing 23 years of warm-season derechos in France: a climatology and investigation of synoptic and environmental changes

Abstract. Derechos are severe convective storms known for producing widespread damaging winds. While less frequent than in the United States of America (USA), derechos also occur in Europe. The notable European event on 18 August 2022 exhibited gusts exceeding 200 km h−1, spanning 1500 km in 12 h. This study presents a first climatology of warm-season derechos in France, identifying 38 events between 2000 and 2022. Typically associated with a southwesterly mid-level circulation, warm-season derechos in France generally initiate in the afternoon and exhibit peak activity in July, with comparable frequencies in June and August. Predominantly impacting the northeast of France, these events exhibit a maximum observed frequency of 0.65 events per year, on average, within a 200 km by 200 km square region. These characteristics are similar to those observed in Germany, with notable differences seen in the USA, where frequencies can attain significantly higher values. The study also examines synoptic and environmental changes linked with analogues of the 500 hPa geopotential height patterns associated with past warm-season derechos, comparing analogues from a relatively distant past (1950–1980) with a recent period (1992–2022). For most events, a notable increase in convective available potential energy (CAPE) is observed, aligning with trends identified in previous studies for southern Europe. However, no consistent change in 0–6 km vertical wind shear is observed in the recent period. These environmental shifts align with higher near-surface temperatures, altered mid-level atmospheric flow patterns and often increased rainfall. The role of anthropogenic climate change in these changes remains uncertain, given potential influences of natural variability factors such as the El Niño–Southern Oscillation (ENSO) or the Atlantic Multidecadal Oscillation (AMO).

Computational study on reactivity, aromaticity, and absorption spectra of chrysene: effect of BN doping and substituents

Abstract Density functional study (DFT) is performed for understanding the reactivity, aromaticity, and UV-visible absorption spectra of chrysene-based materials. Effect of BN doping on the said parameters are analyzed along with the effect of –Me (methyl), –OH (hydroxyl), –CHO (formyl) –COOH (carboxyl) and –CN (cyano) substituents. Global reactivity parameters viz. energy of HOMO (E HOMO), global hardness (η), chemical potential (μ) and electrophilicity (ω) are computed. Nucleus independent chemical shifts (NICS) values are estimated to study the variation in aromaticity. Time dependent density functional theory (TD-DFT) is used to study the UV–Visible absorption spectra. Effects of BN doping and substituents on corresponding dipole moments and band gaps are also analyzed. Presence of BN unit and/or substituents induced considerable impact on global reactivity, dipole moment, band gap and aromaticity of the chosen systems, especially for BN doped chrysene at the edge. Absorption spectra which are red shifted in presence of BN and substituents are mostly found within the UV-region.

Deciphering the Performance Enhancement, Cell Failure Mechanism, and Amelioration Strategy of Sodium Storage in Metal Chalcogenides-Based Andes.

Transition metal chalcogenides (TMCs) emerge as promising anode materials for sodium-ion batteries (SIBs), heralding a new era of energy storage solutions. Despite their potential, the mechanisms underlying their performance enhancement and susceptibility to failure in ether-based electrolytes remain elusive. This study delves into these aspects, employing CoS2 electrodes as a case in point to elucidate the phenomena. Our investigation reveals that CoS2 undergoes a unique irreversible and progressive solid-liquid-solid phase transition from its native state to sodium polysulfides (NaPSs), and ultimately to a Cu1.8S/Co composite, accompanied by a gradual morphological transformation from microspheres to a stable 3D porous architecture. This reconstructed 3D porous structure is pivotal for its exceptional Na+ diffusion kinetics and resilience to cycling-induced stress, being the main reason for ultra-stable cycling and ultrahigh rate capability. Nonetheless, the CoS2 electrode suffers from an inevitable cycle life termination due to the micro-short-circuit induced by Na metal corrosion and separator degradation. Through a comparative analysis of various TMCs, we establish a predictive framework linking electrode longevity to electrode potential and Gibbs free energy. Finally, the cell failure issue is significantly mitigated at a material level (graphene encapsulation) and cell level (polypropylene membrane incorporation) by alleviating the NaPSs shuttling and micro-short-circuit. This article is protected by copyright. All rights reserved.

State-to-state study of non-equilibrium recombination of oxygen and nitrogen molecules.

Rapidly cooled mixtures are of interest for several applications, including hypersonic flows due to the presence of strong cooling temperature gradients in regions such as hypersonic boundary layers and expanding nozzles. There have been very few studies of rapidly cooled mixtures using the high-fidelity rovibrational databases afforded by abinitio potential energy surfaces. This work makes use of existing rovibrational state-specific databases to study rapidly cooled mixtures. In particular, we seek to understand the importance of thermal non-equilibrium in recombining mixtures using both rovibrational and vibrational state-to-state methods for oxygen and nitrogen molecules. We find that although there is significant non-equilibrium during recombination, it is well captured by the vibrational state-specific approach. Finally, we compare the global recombination rate computed based on the state-specific recombination rate coefficients and the global recombination rate computed based on the time local dissociation rate coefficient, which is reversed using the principle of detailed balance. The local dissociation rate coefficient is computed by weighting the state-specific dissociation rate coefficients with the state-specific distribution of energy states. We find a large difference between these rates, highlighting a potential source of errors in hypersonic flow predictions.

Utilization of Multi-Mission Satellite Altimetry for Wave Energy with Site Suitability Analysis using the Analytic Hierarchy Process

Space technology advancements have enabled the acquisition of marine data that support the research on wave energy as an alternative to reduce fossil fuel dependency and mitigate climate change. Malaysia's ocean renewable energy potential lacks attention from local authorities due to insufficient in-situ data, posing challenges in investigating ocean characteristics, such as wave heights. This study investigated Malaysia's wave energy potential using extensive significant wave height data from multiple altimetry missions. The former assessed site suitability using the Analytical Hierarchy Process (AHP) multicriteria analysis, incorporating marine constraints, namely socioeconomic, physical, and environmental factors. The multicriteria findings were integrated into a Geographical Information System (GIS) to improve the site suitability analysis and generate a localized suitability index for wave energy. Validation of satellite altimeter data with in-situ measurements showed a strong correlation and low RMSE. AHP analysis indicated good consistency in the criteria analysis, with a consistency ratio of 0.045, which falls below the limit of 0.1. The coastal and offshore regions of the Malaysian seas are suitable for harnessing wave energy with energy ranges up to 4.21 kW/m. Therefore, this study provides valuable information to stakeholders and the government to increase their interest in wave energy.

Assessment of Wind Resource and Its Energy Potential in Three States of Northwest Nigeria

The growing need for clean energy to address the environmental issues caused by the usage of fossil fuels results to the need for Nigeria to develop an alternative energy from untapped wind which is in abundance in the region. The aim of this study is to evaluate wind power potential and wind energy resources of three locations (Kaduna, Kano and Katsina) of northwestern part of Nigeria. The Nigerian Meteorological agency (NIMET) provided the wind speed data spanning 25 years (1996-2020). In the analysis, Weibull two-parameter statistical model was used. The distribution of wind speed across Nigeria demonstrates that some areas in the North are equipped to generate wind. Microsoft excel was used in analyzing the wind speed data obtained. In addition, evaluation of the region’s wind energy resources shows that Kano recorded the highest potential, with WPD of 443.03 Wm-2 at 10m AGL with annual WED of 4.921 kWhm-2day-1 while Kaduna recorded the lowest potential of 198.43 Wm-2 with annual WED of 2.093 kWhm-2day-1. As a result, Kaduna is found to be ideal for small scale wind power generation, while Kano and Katsina may be suitable for large scale wind power generation.

Investigation of waste LDPE with Pongamia pinnata seed for sustainable resource recovery: Thermodynamics, Kinetics and artificial neural network modeling for co-pyrolysis potential

Pyrolysis conversion offers the advantages of significant waste reduction and potential energy recovery. This work examined the potential of combining plastic and agricultural wastes as pyrolysis feedstocks. The mixture of waste low-density polyethylene and Pongamia pinnata seeds was analysed using differential and thermogravimetric methods. In addition to the Coats-Redfern (CR) method, Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Friedman (FRM), and Kissinger (KN) model-free methods were also applied to calculate the kinetic parameters. The apparent activation energy (Ea) calculation demonstrated that the co-pyrolysis conversion required Ea values of 125–154 kJ mol−1. The artificial neural network (ANN) model was considered to validate thermogravimetric data. The R2 values were near unity in training, validation, and testing conditions, with the minimum possible value for mean square error obtained for the considered heating rates. The Pongamia pinnata seeds and waste plastic mixture could surely be utilized to lessen environmental degradation, add value to leftover seeds and waste low-density polyethylene by extracting fuel for transportation and other commercial activities, and produce industrial chemicals, as found through the kinetic modelling, thermodynamic parameters, and ANN modelling.

Identifying the charge states of carbon vacancies in 4H-SiC by ab initio metadynamics

4H Silicon carbide (4H-SiC) is widely recognized as a highly promising material for high-voltage and high-power electronic applications due to its exceptional properties. The performance of devices based on 4H-SiC is often weakened by the presence of carbon-related point defects, particularly carbon vacancies (VC). The defects of VC introduce deep-level traps (e.g., Z1/2 and EH6/7) that deteriorate device functionality. Experimental and theoretical studies on VC have led to some conflicting results about the charge states of VC, especially for the charge state ordering of EH6/7. We now employ ab initio metadynamics (META) to systematically investigate configuration space including the direction and magnitude of bond distortion and identify the most stable structures of VC. Eventually, the charge states of VC in 4H-SiC are identified. The Z1 (EH6) and Z2 (EH7) indicate transitions from acceptor (donor) levels of VC, located on the h and k sublattice sites, respectively. Z1 and Z2 demonstrate negative-U ordering, characterized by U values of −0.16 and −0.37 eV, respectively. Conversely, EH6 and EH7 display positive-U ordering, with U values of 0.16 and 0.08 eV, respectively. The current results provide insights into the properties of VC in 4H-SiC, highlighting the effectiveness of META in the exploration of complex potential energy surfaces associated with point defects in solids.

Impact of time resolution on estimation of energy savings using a copula-based calibration in UBEM

Urban Building Energy modelling (UBEM) has emerged in the last decade as an important tool to accelerate energy transition in the building sector. To fulfil one of its major purposes - forecasting energy savings for potential energy conservation measures at an urban scale, several challenges are still to be addressed. Two key challenges include: 1) the need to calibrate models with a large number of unknown parameters across numerous buildings (either individually or through archetype representation); 2) the limited availability of high-resolution measured data, which raises concerns about calibrated models based solely on yearly values for accurate energy savings forecast. This study addresses these challenges using a case study of 35 buildings in a district in Stockholm, Sweden. Firstly, a new iterative Approximate Bayesian Computation (ABC) method for calibration is proposed, incorporating a copula-based sampling process at each iteration. Secondly, the new calibration process is applied with three different time resolutions to examine the impact of data resolution on forecasted energy usage, particularly when applied to a classical energy conservation measure. Results demonstrate the efficiency of the new method across the 35 buildings, facilitating the rapid population of a final joint distribution for the nine unknown parameters considered in each building. While the marginals may be strongly influenced by the time resolution, the forecasted energy consumption remains identical across the three analysed time resolutions. However, a noticeable difference is observed when the ECM pertains to a formerly unknown or known parameter.

Molecular dynamics simulations to evaluate the decomposition properties of methane hydrate under different thermodynamic conditions

Understanding the thermodynamic effect on methane hydrate decomposition is beneficial for designing controllable methane recovery processes under conditions of continental margins and oceanic sediments. In this work, we systematically examined the effects of varying temperatures and pressures on the natural gas hydrate decomposition in the presence of 20 mol% methanol through the molecular dynamics approach. Taking advantages of key parameters of angular order parameter (AOP), radial distribution function (RDF), mean square displacement (MSD), and potential energy, we mainly aimed to explore the impact of temperature and pressure on the decomposition of methane hydrate. It can be founded that high temperature is a positive factor for the methane hydrate decomposition, and as the temperature increases from 272.15 K to 277.15 K, the promotion effect becomes more obvious, resulting in a reduction of decomposition time by 3.93 ns. On the contrary, pressure has a negative effect on the methane hydrate decomposition, and as the pressure increases from 1 bar to 200 bar, the inhibitory effect becomes smaller. Additionally, the potential energy as a function of time can be used to evaluate the decomposition rates under different thermodynamic conditions. The obtained results underscore the significant dependence of methane hydrate decomposition rates on temperature and pressure, providing essential guidelines for optimizing gas hydrate decomposition processes.

Theoretical modeling and vibration analysis of composite laminated wing-box structures of hydrogen-electric aircraft under hygrothermal environment

For the sake of achieving the goal of ultra-low or even zero carbon emissions during flight, hydrogen-electric aircraft has been receiving increasing emphasis. Nevertheless, the hydrogen-electric aircraft owns an all-composite fuselage configuration and is subjected hygrothermal environment, which have a significant effect on the aircraft dynamics, especially for wing structure. In this study, an improved orthogonal polynomial solution based on the Rayleigh-Ritz method is developed for the dynamic analysis of composite laminated wing-box structures (CLWBSs) of hydrogen-electric aircraft with humid and hot environment and elastic boundary. In this solution approach, the potential energy, kinetic energy, elastic potential energy and hygrothermal potential energy of CLWBSs are derived from the framework of Kirchhoff thin plate hypothesis. A set of artificial springs is imported to the free edges of CLWBSs to simulate the elastic boundary and connection between two plates. The convergence, accuracy and computational efficiency of the proposed formulation are validated by experiment and finite element analysis. The effect of the coupling parameters and the elastic boundaries due to flexible composite fuselage in hygrothermal environment created by the hydrogen fuel cells are systematically investigated which have been confirmed by theoretical research, finite element analysis and experiment. The related findings indicate that the present approach provided an effective formulation for the vibration analysis and optimization of flexible composite wing-box structures. It can be applied in the field of aerospace and navigation industry at the same time.

Study of Power Sector Reforms for Madhya Pradesh Development

AbstractThe nuclear power industry in India plays a significant role in meeting the country's energy demands and fostering economic growth. This research study explores the need for research in the context of India's nuclear power industry, specifically focusing on Madhya Pradesh (MP). The aim is to investigate the potential of nuclear energy as a clean and sustainable resource for economic development in the region. The study considers the interplay between economic growth, resource reduction, and energy consumption within the state.Highlights of the article importance of nuclear energy in India's overall energy mix and its potential for driving economic progress. The Indian nuclear power industry encompasses various sectors, including industrial, transmission, and commercial. Nuclear energy is recognized as a clean and vital economic resource, capable of providing substantial benefits to the national economy.The focus of this research is MP, the largest state in terms of nuclear power generation in India. The state's economic growth depends on several factors, including energy consumption. To achieve significant improvements in resource reduction and sustainable development, it is crucial to examine the role of nuclear power within the state's energy sector.The research study presented in this article addresses the electricity reform of the Madhya Pradesh State Electricity Board (MPSEB). By evaluating the infrastructure and recent discussions surrounding the Chutka Nuclear Power Plant project, which aims to support the energy sector in the Mandla region, this study aims to contribute to the understanding of the potential economic benefits of nuclear power in MP.The findings from this research will provide valuable insights into the relationship between nuclear energy, economic growth, and sustainable development in the Indian context. It will help policymakers, industry stakeholders, and researchers in formulating strategies and policies that promote the effective utilization of nuclear power as a catalyst for economic progress while ensuring environmental sustainability. This study ultimately contributes to the knowledge base required for harnessing the full potential of nuclear energy in India's energy landscape.

A multiscale thermo-mechanical coupling model for Fiber-Reinforced Cementitious Composite (FRCC)

This paper aims to develop a multiscale thermo-mechanical coupling model across from meso-scale to macro-scale to study the tensile thermos-mechanical behavior of fiber-reinforced cementitious composite (FRCC) on the base of thermodynamics. In meso-scale, the coupling process of thermal effect and the development law of a single crack were creatively presented and formulated in energy potential function. The effects of fiber dispersion on cracking behavior and crack strength of matrix were determined. In macro-scale, the multiple-fine-cracks and strain-hardening/softening behavior under tension were defined and studied. The bridging action stress of fibers is calculated by considering the bonding stress in the interface transition zone (ITZ). The model can be upgraded for FRCC materials ranges from strain-hardening cementitious composite (SHCC) and engineered cementitious composite (ECC). The numerical calculations of the proposed model were conducted based on the Fortran program for validation. The residual tensile strength, multiple-fine-cracks and strain-hardening/softening behaviors of FRCC were predicted. The behaviors of FRCC with different fiber types were accurately captured in a range of temperature from 20°C to 600°C through the comparative study with six groups test results in literatures. A sensibility study was carried out to analyze the impact of modelling parameters and thermal effect on the strain-hardening/softening behaviors of FRCC.

A new ab initio potential energy surface and rovibrational spectra for the N2–N2O complex

We propose a new potential energy surface for the N2–N2O complex, which encompasses the Q3 normal mode for the ν3 antisymmetric stretching coordinate of N2O. The interaction potential energies were obtained at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level with aug-cc-pVTZ basis set. Four-dimensional vibrationally averaged potentials with N2O in the ground and ν3 excited states were generated through integration over the Q3 coordinate. Both potentials exhibit two equivalent skew T-shaped global minima. The rovibrational energies were calculated by employing the radial discrete variable representation/angular finite basis representation approach. The determined fundamental band origin shift of the infrared spectra in the N2O ν3 region, transition frequencies and rotational constants are all consistent with the experimental values.

Quantum Mechanical Comparison between Lithiated and Sodiated Silicon Nanowires

This computational research study will compare the specific charge capacity (SCC) between lithium ions inserted into crystallized silicon (c-Si) nanowires with that of sodium ions inserted into amorphous silicon (a-Si) nanowires. It will be demonstrated that the potential energy V(r) within a lithium–silicon nanowire supports a coherent energy state model with discrete electron particles, while the potential energy of a sodium–silicon nanowire will be discovered to be essentially zero, and, thus, the electron current that travels through a sodiated silicon nanowire will be modeled as a free electron with wave-like characteristics. This is due to the vast differences in the electric fields of lithiated and sodiated silicon nanowires, where the electric fields are of the order of 1010 V/m and 10−15 V/m, respectively. The main reason for the great disparity in electric fields is the presence of optical amplification within lithium ions and the absence of this process within sodium ions. It will be shown that optical amplification develops coherent optical interactions, which is the primary reason for the surge of specific charge capacity in the lithiated silicon nanowire. Conversely, the lack of optical amplification is the reason for the incoherent optical interactions within sodium ions, which is the reason for the low presence of SCC in sodiated silicon nanowires.

Two high-impact extreme precipitation events during the Meiyu season: simulations and their sensitivity to a scale-aware convective parameterization scheme

In this study, we investigate the impact of a scale-aware convective parameterization scheme (CPS) on simulating two high-impact extreme precipitation events during the Meiyu season at a 1 km resolution. Compared with explicit resolving simulation, applying scale-aware CPS mostly affects the atmospheric environment before convection is triggered and the regions outside the convective cell (e.g., stratiform regions) by consuming convective available potential energy (CAPE), which further inhibits precipitation. For the 2019 event, since the explicit resolving simulation underestimates precipitation, applying scale-aware CPS further inhibits precipitation and reduces the skill for the heavy rainfall category. In contrast, for the 2020 event, as the explicit resolving simulation overestimates precipitation, using scale-aware CPS inhibits precipitation and improves the skill of the model. When scale-aware CPS is applied, increasing σ1, which represents the effect of horizontal resolution, the CPS precipitation is reduced and the grid-scale precipitation is increased, but the overall effect inhibits the total precipitation. However, with the increase in σ1, although the number of stations with heavy rainfall (≥50 mm) is reduced, the average precipitation among these stations is increased. Further analysis of those stations with the largest 24 h precipitation and cross sections over regions with large radar reflectivity shows that increasing σ1 reduces the CAPE consumed by CPS and provides a more favorable environment for strong convections and strengthens precipitation. The results of this study may provide useful information for operational model application and may be beneficial to society.

Modulations of dust aerosols on precipitation: Evidence from a typical heavy sandstorm event

Dust aerosols pose significant modulations on precipitation, varying with precipitation intensity. In particular, the microphysical influences of dust aerosols on the clouds and diurnal variations of heavy precipitation exhibit substantial uncertainties. Taking the typical heavy sandstorm event occurring on March 15, 2021 in China as an example, we investigate the distinct modulations of dust aerosols on precipitation by the Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) model and multiple observational and reanalysis data. Note that dust aerosols exert opposite influences on moderate and heavy precipitation. The inhibiting effect of dust aerosols on the intensity of light precipitation was observed as dust aerosols increase atmospheric stability by cooling in the lower layers, warming in the upper layers, reducing CAPE (Convective Available Potential Energy), increasing CIN (Convective Inhibition). Additionally, dust aerosols hinder the transformation of cloud droplets to raindrops, leading to decreased mass of rainwater (Qr) and snow (Qs) in the lower and middle atmosphere. In contrast, dust aerosols delay but intensify heavy rainfalls. During the night of heavy rain, dust aerosols can can warm the lower layers and cool the upper layers, increase CAPE and decrease CIN, thereby enhancing convection, making it easier for small cloud droplets to grow into larger raindrops through collision and coalescence. Simultaneously, small cloud droplets in the mid-levels ascend to higher altitudes where they freeze, transforming into ice particles. This process, coupled with the Bergeron-Findeisen mechanism, enhances the intensity of nighttime. These findings provide novel evidence to improve our understanding of dust aerosols-precipitation interaction.

Theoretical investigation of the silver chalcogenide molecules AgSe and AgTe electronic structure with dipole moment calculation

The spectroscopic constants (Re, Te, ωe, Be) are determined for 46 doublet and quartet low-lying states of the molecules AgTe and AgSe using CASSCF/MRCI (single and double excitations plus Davidson correction) calculations. The equilibrium bond length Re, and the vibrational frequency ωe of the ground state of both molecules have also been investigated using the density functional theory (DFT) incorporating eight different functionals along with different basis sets. The potential energy and permanent dipole moment curves of 23 states of each molecule have been investigated and depicted. This study represents the first theoretical investigation of the molecules AgSe and AgTe.

A plastic Stillinger-Weber potential-based discretized virtual internal bond approach for modeling soft rock fracture and its application in tunnel failure

Soft rocks present some undesirable behaviors, such as low strength, high plasticity and softening. These traits pose challenges in the design and construction of soft rock tunnels. To address these issues and model plastic fracture behaviors of soft rocks, we proposed a plastic Stillinger-Weber (PSW) potential and integrated it into the discretized virtual internal bond (DVIB) model. The PSW-DVIB model combines the strengths of the plastic DVIB and the SW-DVIB models. It not only effectively reproduces the plastic fracture behavior but also accurately reflects the Poisson’s ratio. Moreover, due to the inclusion of fracture energy in the PSW potential, the simulation results are basically mesh size independent. The PSW-DVIB model is then utilized to investigate the failure behaviors of soft rock tunnels. The effects of the coefficient of lateral pressure, in-situ stress, Poisson’s ratio and tunnel shape on tunnel failure are investigated. The simulated results indicate that the coefficient of lateral pressure has significant influence on the failure zone distribution of the surrounding rock. With the coefficient of lateral pressure increasing, the failure degree of surrounding rock decreases firstly and then increases. The optimum coefficients of lateral pressure for the stability of circular, arched and square tunnels are about 1.00, 0.75 and 0.75, respectively. When the in-situ stress or Poisson’s ratio is larger, the influence of the coefficient of lateral pressure on tunnel failure is more obvious. The influence of the coefficient of lateral pressure on square tunnels are more significant than the arched tunnels, and then the circular tunnels. These findings provide valuable insights for the design and construction of soft rock tunnels.