Green Field Conditions Research Articles

Quantifying the response of piled structures from displacements induced by pile installation in soft clay

The impact of pile installation in soft soils on its surroundings has been numerically investigated with a focus on the response of an existing piled structure. The originality is the parameterised 3D Finite Element Analyses of far-field soil-structure-interaction scenarios, <i>i.e.</i>, interactions that are largely driven by mass-displacements. A main finding is that the geometry, that includes the number and length of newly installed and existing piles, the distance between the two pile groups and also the distance to stiff boundaries in the system (in the field and in the numerical analysis), govern the problem to a large extent. Therefore, to simplify the analysis of such complex cases, modification factors for the displacements in greenfield conditions are proposed, to calculate the displacement and structural response of the existing structure. The proposed non-dimensional factors are a function of the length of the newly installed and existing piles and the distance between the two pile groups. No unique solution exists, hence a series of charts have been compiled to provide a first assessment of the impact of an existing piled structure on the induced displacements from the installation of a nearby group of displacement piles in soft soil.

Numerical analysis of relative density effects on shallow TBM tunnel excavation: Ground behavior and principal strains at surface in greenfield conditions

Tunnel construction in urban areas may result in ground deformations that pose a risk to existing buildings and infrastructure; thus, accurate prediction of these induced ground deformations during the design phase is crucial. The paper focuses on the effects of sandy soil relative density on the ground deformations induced by tunnels excavated with Tunnel Boring Machines (TBMs). The study utilizes the Finite Element Method (FEM) and the NorSand model to simulate the behavior of a sandy ground. The validity of the FEM modeling approach is established by comparing predictions with results from six centrifuge tunnel tests from the literature. The centrifuge tests were performed on sand at different relative densities, tunnel diameters, and tunnel depths. The parameters for the NorSand model were determined based on laboratory tests. Only the state parameter was modified to achieve the desired relative density in the numerical simulations. The effects of relative density observed in centrifuge tests (Franza et al., 2019) have been numerically reproduced with no further adjustments of the model parameters. The rich outputs from the numerical models enabled an in-depth investigation of tunnel behavior, yielding new insights into how tunnels respond under varying relative densities, depths, and diameters. A comprehensive analysis of the induced ground deformations caused by shallow tunnels in sandy ground and the potential to damage buildings is included.

Introducing tunnel kinematic constraints into an elastic continuum formulation of tunnel–soil–pipeline interaction

This paper presents a new formulation of the problem of tunnelling effects on pipelines, which incorporates the tunnel kinematic constraints in the tunnel–soil–pipeline interaction analysis. This ‘constrained continuum formulation’ can be considered an extension of the original ‘two-stage’ elastic-continuum method, which traditionally neglects the mutual influence of the pipeline on the tunnel and vice versa. The new approach retains the advantage of using the greenfield condition as an input, but it allows closed-form consideration of the stiffening effect of the tunnel on the soil domain. The paper details the formulation and then provides an investigation into the effect of varying fixities: namely, both as ‘wished-in-place’ tunnels and as evolving, advancing constraints, with the tunnel ‘construction’. Normalised solutions are presented and compared with the previous formulation. In general, the addition of tunnel constraints leads to a stiffer soil action, and thus higher bending stressing in the pipeline; modelling of the tunnel kinematic constraint is conservative. The question of when such analysis is desired is discussed, concluding with a simple-to-use inequality suitable for design.

Axillary shoot proliferation and regeneration of red rose [pisiformis (christ.) D. Sosn. An under thread extinction species endemic to Turkey

In vitro propagation of red rose [Rosa pisiformis (Christ.) D. Sosn.] has great importance in rapid proliferation of species with medicinal features and in culture of healthy plants free from deseases. After a succesfully pre-sterilization procedure, experiments were maintained by two-phase: multiplication phase and rooting of microshoots phase. Micropropagation of Rose was improved, using its nodal segments under different combination of BAP (0, 1.0, 2.0, 0.6 mg/l), NAA (0, 0.1, 0.2, 0.01 mg/l) on Driver and Kuniyuki (DKW) and MS medium in multiplication phase and using distinct compositions of IBA (0, 1.0, 3.0, 5.0 mg/l) and DKW medium in rooting phase. The maximum number of shoots/per plant (22.6) with the highest number of leaves (222.6) were obtained in DKW medium supplemented with 0.6 mgl-1 BAP and 0.01 mg/l NAA. The leaf explants were also used to occur callus in MS with different combinations of BAP and NAA. Good callus formation was obtained with 1:2 ratio of BAP:NAA combination in MS medium. Furthermore, the highest root induction (100%) was achieved in DKW medium consisting of 1 mg/l IBA. The rooted plantlets were transferred to the field after acclimatized in greenfield conditions. The present investigation presents an in vitro protocol for R. pisiformis. Bangladesh J. Bot. 52(4): 949-958, 2023 (December)

Correlation Studies for Morphological and Biomass Traits in Half-sib Progenies of Peltophorum pterocarpum

The current research was conducted on twenty plus trees of Peltophorum pterocarpum from different locations in Bihar to study the association among different morphological and biomass traits. It was found that PPT12 (Rajgir Park) and PPT4 (Muraura, Nalanda) performed better for germination metrics under open field and greenhouse conditions, respectively. PPT6 (Nari, Nalanda) and PPT13 (Sathopur, Nalanda) outperformed all other superior tree progenies in terms of morphological and biomass attributes in green house and open field conditions, respectively. The phenotypic coefficient of variability was greater than the genotypic coefficient of variability for all morphological and biomass variables tested under green house and field conditions, showing that the environment played a greater role. Germination value heritability was found to be high in both environments. High heritability with high genetic advance was associated with shoot length in greenhouse condition, indicating additive gene action. Under greenhouse conditions, the phenotypic correlation coefficients among the seedling parameters evaluated varied from a non-significant 0.211 (P=0.01) between shoot root ratio and root dry weight and between shoot length and collar diameter to a very significant 0.967 (P=0.01).Accessions showing higher values for one or the other attributes could be selected as parents for further improvement.

Predicting Tunnel-Induced Settlement in Cohesionless soils in Greenfield Condition

Rapid population growth and increasing congestion worldwide are placing greater demands on existing infrastructure. A solution to this problem is the use of tunnels to construct underground transportation systems. However, tunnelling induces settlement troughs that may result in severe or possibly irreparable damage to nearby infrastructure. For this reason, the effects of tunnelling must be well understood and predicted in the tunnel design stage, to prevent structural damage due to design oversights. Although tunnelling in clay has been extensively studied by previous researchers, the literature lacks reliable settlement estimation techniques for tunnels embedded in granular soil media. In this study, an extensive parametric analysis is conducted to examine the effects of the tunnel diameter, embedment depth, soil density, and shield conicity (tail void gap) on tunnel-induced settlement. Based on the results of the parametric analysis, the authors propose an effective, user-friendly solution that utilizes artificial intelligence software to predict tunnel-induced surface subsidence. The reliability and accuracy of the proposed solution are demonstrated by comparisons with 12 different sets of measured field data.

Longitudinal Vibrations Emitted by a Tunnel Boring Machine (Tbm) in Greenfield Conditions. A Numerical Resolution Based on a In-Situcampaign

Longitudinal Vibrations Emitted by a Tunnel Boring Machine (Tbm) in Greenfield Conditions. A Numerical Resolution Based on a In-Situcampaign

Exploring the potential of P solubilizing rhizobacteria for enhanced yield and quality in turmeric (Curcuma longa L.)

The study focused on isolation and characterization of a bevy of phosphorus solubilizing bacteria (PSB) and exploring the effects of the most promising PSB on yield and quality of turmeric. For this purpose, several bacterial strains isolated from the rhizosphere of turmeric grown across India were assessed for their capacity to solubilize tri-calcium phosphate (TCP) and di-calcium phosphate (DCP) under in vitro condition and in liquid medium. The soluble P turnover by the promising PSB was then investigated in soil per se and their effects were further validated in turmeric under both green house and field conditions for two successive years. The results revealed that Bacillus safensis (NCBI-MT192800), B. marisflavi (NCBI-MT 192801), B. cereus (NCBI- MT192803) and Pseudomonas aeruginosa (NCBI-MZ 540872) released significantly greater levels of labile P in the liquid medium due to their capacity to produce appreciable amounts of organic acids (gluconic, α ketogluconic, succinic, oxalic and tartaric). Green house studies on turmeric indicated that soil available P was significantly higher in the treatments involving PSB suggesting enhanced P solubilization and the treatment with B. safensis + 75 % P as rock phosphate (RP) increased rhizome yield by 129.0 % compared to the treatment with 100 % P applied as RP. The positive effects of PSB were also reflected in field experiments, wherein the treatments with combined application of B. safensis with 50 % or 75 % or 100 % P significantly increased soil available P by 143.0 – 246.0 %, rhizome yield by 29.0 – 120.0 %, P uptake by 51.0 – 223.0 % and curcumin content by 30.0 – 32.5 % compared to control (100 % P as RP). The use of B. safensis ensured 25.0 % reduction in exogenous inorganic P application while simultaneously enhancing turmeric yield and quality in P deficient soil.

Physical modelling of EPB TBM in dry sand and greenfield conditions

This paper presents the results obtained during the first stage of a large experimental project based on the so-called ‘Earth Pressure Balanced Shield’ (EPBS) method adapted to tunnelling in soft ground. In the first part, the details of a 1 g laboratory model of EPBS specially improved within the framework of this project are presented. In particular, the new elements of the experimental setup, its instrumentations, the machine control, the preparation of the soil mass model are detailed. In the second part, the results obtained from this new EPBS model for two excavation tests, carried out in purely frictional soil mass (dry fine silica sand) and greenfield conditions (without neighbouring structures), are presented. The analysis concerns both soil surface and subsurface displacements, vertical and horizontal stress evolution in the ground when the Tunnel Boring Machine (TBM) progresses. It confirms that the highly sophisticated design of the machine allows to simulate the 3D excavation process closely, and to reproduce kinematic phenomena in the ground being in good agreement with those observed in the practice. In the case of the steady state excavation imposed during the tests, the extension of the TBM impact zone could also be identified based on the measured stress and strain variations of the ground.

Twin tunnelling caused distortions and its effect on a hospital building on mixed ground conditions

ABSTRACT An extensive geotechnical assessment of a hospital building under-crossed by twin tunnels is presented in this paper. The case study considered in the study is Phase III of Delhi Metro Gray line, which has been built recently using Tunnel Boring Machine. Finite element analysis was carried out to simulate the construction of two tunnels underneath the building, and the soil is simulated using an advanced constitutive model. The numerical model was validated against the field monitoring data, and the effect of tunnelling on the building deformation is also studied. Also, the comparison of building settlements with greenfield conditions is carried out. The study showed that the building influences the pattern of the settlement trough. Quantitative study of the settlement showed that there was no undue distress to the building due to the construction of twin tunnels, suggesting the safe crossing of twin tunnel below hospital building.

Predicted and observed behaviour of pre-installed barriers for the mitigation of tunnelling effects

Tunnelling activities in densely urbanised areas are likely to interfere with existing structures, often requiring the adoption of techniques to mitigate the effects of the induced ground movements. If the tunnel passes to the side of an existing structure, embedded barriers pre-installed between the tunnel and the buildings can act as a passive intervention reducing the displacements that would occur in greenfield conditions. A reliable prediction of the displacement field induced in the presence and the absence of the barrier is, therefore, of primary importance for the design of such a mitigation measure. In this respect, this paper discusses the efficiency of a barrier made of a line of bored piles through the comparison of field monitoring data from a test site in Rome with the results of soil-structure interaction (SSI) FE analyses and simple empirical relationships. Three numerical procedures to simulate plane-strain tunnel excavation were adopted to back-analyse the settlement trough induced at the ground surface by the first passing tunnel. The comparison between the observed and computed settlement profiles permitted to identify the most reliable procedure for 2D simulations of tunnelling excavation which are usually adopted in routine analyses, thus providing some useful guidance for a rational design of the intervention.

Assessing the Economic Risk of Building Damage due to the Tunneling-Induced Settlement Using Monte Carlo Simulations and BIM

Due to the increasing use of underground space to align with sustainability needs, geohazard risk assessments have become a valuable tool for decision-making. One common issue in relation to urban geohazard assessments relates to ground movements due to tunneling affecting adjacent buildings. A framework for assessing costs related to subsequent building damage, using integrated data, statistics and considering the uncertainties involved, is presented in this paper. The proposed methodology provides an integration of Monte Carlo simulations to support uncertainty estimations with an analysis for building-damage cost risk due to tunneling-induced settlements. The analysis involves analytical models using green-field conditions and a typically used building damage assessment method. BIM is capable of collating, combining and visualizing information with advanced analysis techniques into a risk-based tool. The resulting tool provides a clear way of assessing building-damage costs risk due to tunneling-induced settlements. This uses a BIM-based environment and incorporates 3D visualizations and an integrated analysis via MATLAB to reveal and highlight hazardous areas and the severity of economic risk along the tunneling route. This informs the need for additional ground investigations or secondary analyses to ensure engineering processes reduce or remove the risk of economic damage and advance sustainable decision-making.

Effect of a row of soldier piles on the settlement of adjacent buildings due to tunnelling: numerical study

ABSTRACT The shallow tunnelling with large diameter leads to the vertical and lateral ground movements, which could adversely affect the abutting structures. Preventive measures such as diaphragm walls, jet grouting columns, and a row of soldier piles can effectively protect adjacent structures from possible damages. This research specifically assesses the effectiveness of a row of soldier piles to reduce settlements of adjacent buildings using three-dimensional simulations with the finite difference approach. Moreover, the relationship between the performance and major geometrical parameters such as distance from the tunnel axis and piles length in greenfield conditions are studied and evaluated. The effectiveness of a row of piles on adjacent buildings to reduce displacements is also investigated and discussed. The simulation results show a strong relationship between the length of piles and pile spacing in displacement reduction. Piles should be founded at least half a tunnel diameter below the invert, and larger distances (i.e. 4 and 5 times of pile diameter) in a row of piles are also useful in preventing the collapse of adjacent buildings as they can cause a substantial reduction in horizontal displacements.

Biological control of mustard blight caused by Alternaria brassicae using plant growth promoting bacteria

Indian mustard (Brassica juncea) is an important oilseed crop in India. Among various diseases infecting mustard crop, Alternaria leaf spot also known as Alternaria blight is incited by fungus Alternaria brassicae, which majorly affects the crop production leading to a yield loss of up to 70 %. The disease is controlled by application of different fungicides prior to winter rains but it is costly and also cause pollution in the environment. This investigation was designed to explore the potential of rhizosphere bacteria to use as bio control agents for suppression of the disease. Total of sixteen bacterial isolates were isolated from the rhizosphere of mustard, tomato and brinjal and they were screened for their antagonistic activity against A. brassicae in vitro and in vivo conditions. Out of sixteen isolates, two bacterial isolates (B3 and B12) showed maximum inhibition (35 % and 38.6 % respectively) against the pathogen and also displayed high degree of secondary metabolite formation. These two bacterial isolates molecularly characterized as Pseudomonas fluorescens were further tested in green house and field conditions through seed bacterization treatment for disease suppression. Mustard seeds were treated with the bacterial solution overnight and were sown in pots and fields the next day. It was found that the disease incidence percentage of B3 and B12 was 32 % and 35 % respectively compared to control with 62.8 %. The results of the above study were highly significant in evaluation of PGPR against A. brassicae.

Isolation and identification of Rhizobium from non-saline coastal soils of Bangladesh and preparation of mother culture

Nitrogen is the essential mineral macro nutrients which are required for the maximum magnification and yield of agriculturally paramount crops. Microbial inoculants may supplement and abbreviate the dependency on synthetic costly N-fertilizers in reverence of crop yield. The categorical objectives of the research works are to isolate and identify the Rhizobium from culled soils. The ability of soil microorganisms to fix atmospheric nitrogen is an important trait in promoting plant growth and increasing crop yield. The study was conducted for the isolation and identification of nitrogen fixing bacteria from saline and non-saline soils of different locations of tidal floodplain region of Bangladesh. Six Rhizobium strains were isolated and purified. The isolates were preliminary identified on the basis of their morphological and biochemical characteristics. Based on the results, it can be concluded that the isolates possess great potential to be developed as biofertilizers to enhance soil fertility and plant growth. However, their performance under green house and field conditions should be assessed afore being recommended for biofertilizer production and their applications.
 Asian J. Med. Biol. Res. June 2020, 6(2): 222-228

Twin EPB tunneling-induced deformation and assessment of a historical masonry building on Shanghai soft clay

This paper presents a comprehensive geotechnical and structural investigation of a historical multistory masonry building undercrossed by twin mechanized metro tunnels. The prototype is the case of the Shanghai Metro Line 11, which was recently constructed in Shanghai clay using two EPB machines. Field instrumentation is conducted before, during and after tunneling. The settlements along the greenfield surface and building sections are measured. A detailed three-dimensional finite element (FE) model is developed to reproduce the twin tunneling process under the masonry building characterized by the presence of uneven settlements to capture the interaction phenomenon occuring between the twin tunnels during construction. An advanced constitutive model, capable of simulating the behavior of Shanghai clay under the excavation, is employed for the numerical analyses. The FE model is first validated against a set of field instrumentation data, including both greenfield and building surface settlements in cases of single-tunnel passage and double-tunnel passage. Further analyses of the effect of the building presence on the ground movements are subsequently conducted. The results highlight that the presence of the building affects the settlement profiles and that significant differences are observed compared to greenfield conditions. The volume loss of the surface settlement trough after the passage of first tunel and twin tunnels is observed to be approximate 0.58% and 1.02%, respectively. A quantified assessment of the additional deformation of the historical building considering the existing deformation is conducted. No obvious damage to the building is observed during and after the tunnel drives, which confirms the successful tunnel passage beneath the historical building.

Influence of Tunneling in Cohesionless Soil for Different Tunnel Geometry and Volume Loss under Greenfield Condition

This paper presents the numerical analysis of settlement to profile the vulnerable zone or influence zone due to tunneling activities in cohesionless deposits for free field or Greenfield conditions. The analysis considers the factors like saturated density (γsat), unsaturated density (γunsat), angle of shearing resistance (φ), deformation modulus (ES), volume loss (VL), and the support pressure of the shield head at the tunnel face. The obtained results using a finite element program (FEM) PLAXIS 3D are compared with measured and predicted surface settlement using field measuring instruments, and analytical and empirical solution show a reasonable agreement and are found to be conservative. From literature, for Greenfield condition the ground settlement equal to 10 mm is taken as the minimum value to map the influencing zone considering the fact that the structure which lies beyond this zone would undergo negligible settlement. Settlement trough and 10 mm settlement contour characteristics are presented for different tunnel sizes placed at the same depth and the same tunnel size placed at different depths, respectively. Various influencing zones are arrived for the sandy grounds of different denseness based on the parametrical studies involving parameters such as tunnel size “D,” tunnel axis depth “z,” and volume loss “VL.”

Structural Evaluation of Masonry Sewer Pipes Under Transverse Settlement Due to Tunneling

The intention of this research is to perform structural evaluation on masonry sanitary sewer pipes impacted by tunnel excavation. Until about 1900, it was common to use several layers of brick to construct municipal sanitary sewer lines, and currently thousands of miles of brick sewer lines are still in service. The construction of new underground facilities inevitably disturbs the soil above and will have an impact on the existing masonry sanitary sewer pipes within the zone of influence of the excavation. Masonry pipes are typically susceptible to the longitudinal interaction failure mechanism at the hogging zone of the settlement trough due to their low tensile capacity. In this research standard egg-shaped section for brick sewer were subjected to ground settlements obtained using Attewell method. The greenfield condition is assumed to be applicable with homogeneous ground conditions. The impact of the depth to the tunnel axis and trough width parameter on the settlement trough and associated strains developed in the pipes are subjected to investigation. Tensile strain developed due to axial strain and bending moment are calculated for five different section sizes. Mitigation measures and recommendations are provided

Structural Evaluation of Masonry Sewer Pipes Under Transverse Settlement Due to Tunneling

The intention of this research is to perform structural evaluation on masonry sanitary sewer pipes impacted by tunnel excavation. Until about 1900, it was common to use several layers of brick to construct municipal sanitary sewer lines, and currently thousands of miles of brick sewer lines are still in service. The construction of new underground facilities inevitably disturbs the soil above and will have an impact on the existing masonry sanitary sewer pipes within the zone of influence of the excavation. Masonry pipes are typically susceptible to the longitudinal interaction failure mechanism at the hogging zone of the settlement trough due to their low tensile capacity. In this research standard egg-shaped section for brick sewer were subjected to ground settlements obtained using Attewell method. The greenfield condition is assumed to be applicable with homogeneous ground conditions. The impact of the depth to the tunnel axis and trough width parameter on the settlement trough and associated strains developed in the pipes are subjected to investigation. Tensile strain developed due to axial strain and bending moment are calculated for five different section sizes. Mitigation measures and recommendations are provided

Application of rice (Oryza sativa L.) root endophytic diazotrophic Azotobacter sp. strain Avi2 (MCC 3432) can increase rice yield under green house and field condition

Use of plant-associated beneficial microbes, especially endophytes are getting popular day by day as they occupy a relatively privileged niche inside different plant tissues with lesser competition for food and shelter than rhizosphere. The effects of different physical factors like temperature, rainfall, and seasonal variation and UV radiation on plant growth promoting endophytic communities are less pronounced than those on the rhizospheric and phylloplane microbes. This present work has been compromised with further utilization of an indigenous rice (Oryza sativa L.) root endophytic Azotobacter sp. strain Avi2 (MCC 3432) (AzA) as a bio-formulation for sustainable rice production based on several physiological parameters (plant height, root length/weight, leaf area, yield, chlorophyll contain), in-vitro comparative plant growth promoting assays, greenhouse and field experiments (dry and wet season). Treatments with AzA exhibited higher yield as well as maximal chlorophyll fluorescence (Fm) of flag leaves in flowering and grain filling stages indicating higher photosynthetic rates. Scanning electron microscopic image of rice roots demonstrated accumulation of bacterial biofilm at the junction of primary and lateral root confirming the root-colonizing ability of the bacterium. The results of the study were quite encouraging as AzA exhibited better vegetative and reproductive growth of rice in pot and field experiment compared to formulated rhizospheric Azotobacter sp. (commercial product). Apart from that plants treated with AzA (supplemented 50% nitrogenous fertilizer of recommended dose) exhibited similar yield parameters when it was compared with the recommended dose of fertilizer (RDF; 120:60:60 mg N:P:K kg−1 soil/ without any bacterial). Therefore, it can be concluded that application of this plant growth promoting endophyte can reduce a substantial amount of N-fertilizer for field application.