Research of stress-deformed state of the rammed monolithic reinforced concrete cone-shaped piles with side and bottom forms from crushed stones

Relevance. In the construction of buildings and structures, driven piles with a square cross section are most widely used. To install them in the working position, the percussion method is used. However, in cramped conditions, shock loads can lead to dangerous conditions and destruction of structures of nearby buildings. In such a situation, it is necessary to use rammed piles, since technological solutions for their construction are not associated with shock effects on the soil. One such solution is the new rammed cone-shaped pile design, which is installed without excavation. The aim of the study is to analyze the influence of the geometric parameters of the pile on its bearing capacity under the action of external loads, in particular, the angle of its taper. Methods. The results of a numerical analysis of the stress-strain state of a pile operating in a soil massif were obtained by the finite element method. Results. In the computational study, a comparative analysis of the state of piles of different lengths and geometries under the action of external loads was carried out. The influence of the angle of inclination of the lateral surface of the pile on its bearing capacity is considered. Rationalization of the pile design was carried out taking into account the total costs of building materials. Variants of geometric and design solutions for piles with a length L from 1 to 10 m are proposed. In subsequent articles, it is proposed to consider the effect on the bearing capacity of the pile of the geometric parameters of the crushed stone shell and the lower crushed stone spherical expansion, as well as to carry out a comparative analysis of the numerical results with experimental data obtained in laboratory and field conditions.

Mitigation translocation for conservation of New Zealand skinks

<p>Worldwide, human development is leading to the expansion and intensification of land use, with increasing encroachment on natural habitats. A rising awareness of the deleterious effects of habitat destruction on species and ecosystems has increased the use of strategies intended to mitigate these negative impacts. One increasingly common strategy is mitigation translocation, the movement of living organisms from a future development site to another location in an effort to mitigate damage caused. Mitigation translocations may be implemented due to legislation or regulations in many jurisdictions, and in many instances command more resources than purely conservation-motivated translocations. Although they are intended to reduce or offset harm, the effectiveness of mitigation translocations as a conservation strategy has been questioned. I investigated the effectiveness of mitigation translocations for achieving conservation outcomes, using the study system of endemic New Zealand skinks. New Zealand’s skinks show a high level of endemism, are threatened by habitat loss and predation by introduced mammals, and are increasingly subject to mitigation translocations, making them an ideal study system for investigating mitigation outcomes. I investigated: whether mitigation translocations are meeting conservation goals; how the implementation and legal requirements of mitigation translocation relate to conservation goals; and how mitigation translocation practices might be improved to achieve better conservation outcomes. A technique used in mitigation translocations of lizards in New Zealand is the construction of rock piles as habitat enhancement at the receiving site. I developed a novel use of computer game physics software to model the three-dimensional interstitial spaces within such rock piles, and used this model to design rock piles with the aim of protecting translocated skinks from mice (Mus musculus), New Zealand’s smallest introduced mammalian predator. The protection is achieved by selecting rocks to optimise the size of interstitial spaces to be accessible to skinks but not to the larger mice (or other larger predators). This rock pile design could be used to improve survival of skinks both in translocations and other situations such as backyard conservation or restoration. The modelling technique I developed could be used for investigation of refuge space more widely, for instance in other terrestrial systems or aquatic systems. I also took part in a mitigation translocation of lizards at Transmission Gully near Wellington, New Zealand. I used this translocation to test my rock pile design, and as a case study of the challenges facing mitigation translocations and the barriers to conservation success. In addition, I revisited nine historical mitigation translocations of skinks (7–14 years post translocation), took surveys of current populations to assess their success at meeting conservation goals, and found a success rate of 22%, considerably lower than conservation translocations of New Zealand skinks (success rate of 88.9%). Despite this, all but one met their goals of fulfilling legislative requirements. Mitigation translocations fail to result in conservation benefit due to their implementation and goals. The goals of mitigation translocations are rooted in legislation, and vary due to inconsistent application of relevant laws (in New Zealand, the Wildlife Act 1953 and the Resource Management Act 1991), and the fact that the requirements under these laws do not necessarily reflect conservation goals. Additionally, mitigation translocations may be undertaken even when evidence indicates that meaningful conservation outcomes are unlikely (as in the case of the translocation at Transmission Gully). Failure may also be due to poor implementation; examples from case studies here include failure to control predators, low standards of planting at receptor sites, and small founder populations. To improve conservation outcomes, legal requirements for mitigation translocations should be implemented to require biologically-relevant goals (including a no net loss of biodiversity standard) and management techniques, and alternative methods of meeting conservation goals should be considered where appropriate.</p>

Mitigation translocation for conservation of New Zealand skinks

<p>Worldwide, human development is leading to the expansion and intensification of land use, with increasing encroachment on natural habitats. A rising awareness of the deleterious effects of habitat destruction on species and ecosystems has increased the use of strategies intended to mitigate these negative impacts. One increasingly common strategy is mitigation translocation, the movement of living organisms from a future development site to another location in an effort to mitigate damage caused. Mitigation translocations may be implemented due to legislation or regulations in many jurisdictions, and in many instances command more resources than purely conservation-motivated translocations. Although they are intended to reduce or offset harm, the effectiveness of mitigation translocations as a conservation strategy has been questioned. I investigated the effectiveness of mitigation translocations for achieving conservation outcomes, using the study system of endemic New Zealand skinks. New Zealand’s skinks show a high level of endemism, are threatened by habitat loss and predation by introduced mammals, and are increasingly subject to mitigation translocations, making them an ideal study system for investigating mitigation outcomes. I investigated: whether mitigation translocations are meeting conservation goals; how the implementation and legal requirements of mitigation translocation relate to conservation goals; and how mitigation translocation practices might be improved to achieve better conservation outcomes. A technique used in mitigation translocations of lizards in New Zealand is the construction of rock piles as habitat enhancement at the receiving site. I developed a novel use of computer game physics software to model the three-dimensional interstitial spaces within such rock piles, and used this model to design rock piles with the aim of protecting translocated skinks from mice (Mus musculus), New Zealand’s smallest introduced mammalian predator. The protection is achieved by selecting rocks to optimise the size of interstitial spaces to be accessible to skinks but not to the larger mice (or other larger predators). This rock pile design could be used to improve survival of skinks both in translocations and other situations such as backyard conservation or restoration. The modelling technique I developed could be used for investigation of refuge space more widely, for instance in other terrestrial systems or aquatic systems. I also took part in a mitigation translocation of lizards at Transmission Gully near Wellington, New Zealand. I used this translocation to test my rock pile design, and as a case study of the challenges facing mitigation translocations and the barriers to conservation success. In addition, I revisited nine historical mitigation translocations of skinks (7–14 years post translocation), took surveys of current populations to assess their success at meeting conservation goals, and found a success rate of 22%, considerably lower than conservation translocations of New Zealand skinks (success rate of 88.9%). Despite this, all but one met their goals of fulfilling legislative requirements. Mitigation translocations fail to result in conservation benefit due to their implementation and goals. The goals of mitigation translocations are rooted in legislation, and vary due to inconsistent application of relevant laws (in New Zealand, the Wildlife Act 1953 and the Resource Management Act 1991), and the fact that the requirements under these laws do not necessarily reflect conservation goals. Additionally, mitigation translocations may be undertaken even when evidence indicates that meaningful conservation outcomes are unlikely (as in the case of the translocation at Transmission Gully). Failure may also be due to poor implementation; examples from case studies here include failure to control predators, low standards of planting at receptor sites, and small founder populations. To improve conservation outcomes, legal requirements for mitigation translocations should be implemented to require biologically-relevant goals (including a no net loss of biodiversity standard) and management techniques, and alternative methods of meeting conservation goals should be considered where appropriate.</p>

Evaluation of the Static Design Procedure in the Canadian Foundation Engineering Manual for Piles in Cohesionless Soil

Piles provide a convenient solution for heavy structures, where the foundation soil bearing capacity, or the tolerable settlement may be exceeded due to the applied loads. In cohesionless soils, the two frequently used pile installation methods are driving and drilling (or boring). This paper reviews the results of a large database of pile load tests of driven and drilled piles in cohesionless soils at various locations worldwide. The load test results are compared with the static analysis design method for single piles recommended in the Canadian Foundation Engineering Manual (CFEM) and other codes and standards such as the American Association of State Highway and Transportation Officials, Federal Highway Administration, American Petroleum Institute, Eurocode, and the Naval Facilities Engineering Command. An improved pile design procedure is proposed linking the pile design coefficients and to the friction angle of the soil, rather than employing the generalized soil type grouping scheme previously used in the CFEM. This improvement included in the new version of the CFEM 2021 produces a more unified value of the pile capacity calculated by different designers, reducing the obtained design capacity discrepancies.

A CASE STUDY ON CAUSATION OF THE LANDSLIDE IN PORONG-SIDOARJO FOR ROAD CONSTRUCTION WITH HIGH EMBANKMENTS ELEVATION

Landslides occur in virtually every region of the world under diverse environmental conditions and topographies. These events negatively impact humans, resulting in countless casualties. Therefore, this research aims to determine the causes of landslides on man-made national road embankments in East Java, Indonesia. In addition, the occurrences at high elevations, despite reinforcement with soil retaining walls and group pile foundations, appear to be major sources of concern. In the present study, back analysis is conducted to evaluate the conditions of soil subgrade, existing pile capacity, and the effects of groundwater table on embankment stability, as slides typically occur after intense rainfall. Moreover, a stability analysis is carried out using the limit equilibrium process, and the embankment capacity assessment incorporates the anti-slide pile design method. The results show that the landslides are caused by varying soil depths. However, in a landslide embankment section, the soft soil depth appears deeper, compared to the middle zone, where soil data are employed in the existing reinforcement design. Furthermore, the overall stability evaluation for sliding requires wider application in anti-slide pile planning to complement the passive/active stress assessments on the retaining wall. Planning for anti-slide pile design is more often done using active and passive pressure calculations compared to overall stability calculations. Therefore, the results of this study can be used as suggestions for further planning, especially those related to overall stability.

Influence of degree of saturation in the dynamic stress transmission to a deep foundation

The structural design of deep foundations depends on both the applied loads and the soil that will support them. However, during an earthquake this process reverses, and the seismic stresses are transmitted towards the structure through the soil. Proper design of deep foundations must account for the lateral loads imposed on the foundations by the dynamic loading. In order to assess the influence of soil saturation in the transmission of a dynamic load to a foundation, a dynamic lateral load pile design was performed using Reese’s p-y curve method. A series of suction-controlled dynamic triaxial tests were performed to obtain the Modulus of subgrade reaction at different matric suctions and seismic coefficients were back-calculated to perform structural designs. In general terms, it was observed that contemplating a saturated soil in the dynamic lateral load pile design does not represent the critical load case for seismic analysis.