Hasil untuk "Engineering geology. Rock mechanics. Soil mechanics. Underground construction"

Renato Pereira, José Muralha, Luís Lamas

Este artigo explora a aplicação de métodos probabilísticos na análise da fiabilidade e no dimensionamento do reforço de taludes rochosos sujeitos a mecanismos de rotura planar. O estudo incide no caso de um maciço rochoso intersetado por uma família de descontinuidades paralela à face do talude. O volume com potencial de instabilização é idealizado como um modelo de blocos, para o qual se desenvolve uma formulação em sistemas de componentes. Como termo de comparação, analisa-se igualmente um modelo simplificado que considera o mesmo volume como um bloco único. Os resultados evidenciam a influência da inclinação do plano de deslizamento. Verifica-se que o modelo constituído por múltiplos blocos conduz a índices de fiabilidade inferiores. Contudo, a sua utilização para o dimensionamento probabilístico do reforço tem vantagens apenas para inclinações baixas do plano de deslizamento. A análise sugere ainda que o modelo de blocos múltiplos pode ser adequadamente representado por um modelo simplificado de dois blocos.

Erlangga Putranindya, H. Setiawan, Doni Prakasa Eka Putra et al.

The waterway tunnel at Wado Hydropower 50 MW applies underground tunneling construction with a diameter of 6 meters and a tunnel length of 1.860 meters. In 2019, PT Waskita Karya conducted the planning stage for the waterway tunnel at Wado Hydropower. In this research, an evaluation of the engineering geology condition comprised of five aspects, including geomorphology, lithology, geological structure, groundwater level and rock mass quality of the research area. This research was conducted through geological surface mapping, core sample subsurface analysis, laboratory tests, and rock mass classification. Geological surface mapping was carried out on 1,5 x 2,5 kilometers in a waterway tunnel area to acquire the geomorphology, lithology, and geological structure data. Core box samples were analyzed from six core samples obtained along the tunnel for the rock mass quality and groundwater level. Laboratory tests were conducted to evaluate the physical, mechanical, and mineralogical variations of the rocks and soils. Rock Mass Rating (RMR) and Geological Strength Index (GSI) are two methods that were used in the analysis of rock mass quality. As a result, the geomorphological condition of the research area was classified into moderate and steep volcanic hill slopes. Meanwhile, the lithological condition comprised of andesite breccia I and andesite breccia II units. Geological structures of dextral faults were found at one observation station, and there was a topographic alignment pattern in the research area. Groundwater level was at 327-357 meters which is above the waterway tunnel elevation of 315-313 meters above sea level. Finally, the rock mass in the research area consists of poor, fair, and good qualities with RMR values ranging between 36.0 to 63.6 and GSI values of 30.0 to 84.7. In conclusion, the rock mass classification of the research area was affected by the lithological and weathering conditions.

Guangyou Zhu, Xi Li, Bin Zhao et al.

Abstract The 10 000‐m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin. However, major challenges such as the genesis of dolomite, the formation time of high‐quality reservoirs, and the preservation mechanism of reservoirs have always limited exploration decision‐making. This research systematically elaborates on the genesis and reservoir‐forming mechanisms of Sinian–Cambrian dolomite, discussing the ancient marine environment where microorganisms and dolomite develop, which controls the formation of large‐scale Precambrian–Cambrian dolomite. The periodic changes in Mg isotopes and sedimentary cycles show that the thick‐layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale. Lattice defects and dolomite embryos can promote dolomitization. By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights, the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed, and the mechanism of dolomitization was also demonstrated. The properties of calcite and dolomite (104)/(110) grain boundaries and their dissolution mechanism in carbonate solution were revealed, showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs. The in situ laser U‐Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks. This research also proposed that dolomitization occurred during the quasi‐contemporaneous or shallow‐burial periods within 50 Ma after deposition and pores formed during the quasi‐contemporaneous to the early diagenetic periods. And it was clear that the quasi‐contemporaneous dolomitization was the key period for reservoir formation. The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large‐scale dolomite reservoirs. It clarifies the targets for oil and gas exploration at depths over 10 000 m. The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10 000‐m deep oil exploration.

Chunde Piao, Yanzhu Yin, Zhihao He et al.

Abstract Coal mining induces changes in the nature of rock and soil bodies, as well as hydrogeological conditions, which can easily trigger the occurrence of geological disasters such as water inrush, movement of the coal seam roof and floor, and rock burst. Transparency in coal mine geological conditions provides technical support for intelligent coal mining and geological disaster prevention. In this sense, it is of great significance to address the requirements for informatizing coal mine geological conditions, dynamically adjust sensing parameters, and accurately identify disaster characteristics so as to prevent and control coal mine geological disasters. This paper examines the various action fields associated with geological disasters in mining faces and scrutinizes the types and sensing parameters of geological disasters resulting from coal seam mining. On this basis, it summarizes a distributed fiber‐optic sensing technology framework for transparent geology in coal mines. Combined with the multi‐field monitoring characteristics of the strain field, the temperature field, and the vibration field of distributed optical fiber sensing technology, parameters such as the strain increment ratio, the aquifer temperature gradient, and the acoustic wave amplitude are extracted as eigenvalues for identifying rock breaking, aquifer water level, and water cut range, and a multi‐field sensing method is established for identifying the characteristics of mining‐induced rock mass disasters. The development direction of transparent geology based on optical fiber sensing technology is proposed in terms of the aspects of sensing optical fiber structure for large deformation monitoring, identification accuracy of optical fiber acoustic signals, multi‐parameter monitoring, and early warning methods.

Xuming Zhu, Chaoyang Ma, Tong Zhou et al.

The measurement of rock mechanics parameters is the basis for the classification of surrounding rock and the design and optimization of supporting parameters in underground engineering. Therefore, the rapid and accurate measurement of rock mechanics parameters is of great significance in ensuring the safe and efficient construction of underground engineering. However, there are still some problems to be solved in the determination of rock mechanics parameters, such as complicated process, long time consuming and high cost. To solve the above problems, a method of rock mechanical parameters determination while drilling based on the hunter-prey optimizer (HPO)-backpropagation (BP) neural network is proposed. Laboratory rock drilling tests and rock mechanical parameters determination tests are carried out. Based on the HPO-BP neural network method, a relationship model between drilling engineering parameters and rock mechanical parameters is established. The results show that there is little difference between the rock mechanical parameters obtained by the verification centralized test and the predicted rock mechanical parameters. The determining coefficients R2 of uniaxial compressive strength, cohesion force c, and internal friction angle φ are 0.9778, 0.9772, and 0.9817, respectively, and the mean difference rates are 1.36%, 3.78%, and 0.81%, respectively. It is proved that the relationship model between drilling engineering parameters and rock mechanics parameters based on the HPO-BP neural network has a good effect on the prediction of rock mechanics parameters, and can effectively measure rock c–φ parameters quickly and accurately.

Tao Xu

With the deepening of teaching reform, the state has increasingly attached importance to undergraduate education. To meet the needs of economic and social development, the talent training models and objectives of undergraduate colleges have undergone significant changes, and new teaching concepts have emerged one after another. Engineering education accreditation is a key measure to improve educational quality and an important guarantee for comprehensively enhancing the quality of curriculum construction. "Rock Mechanics" is a basic course for the geological engineering major, serving as a crucial link to help students master core professional knowledge and develop practical abilities. However, the traditional teaching method, which focuses on knowledge indoctrination, is difficult to meet the requirements of engineering education accreditation and the actual needs of students' diversified development. Therefore, strengthening teaching reform is imperative. Under the background of engineering education accreditation, this paper explores the teaching reform path of the "Rock Mechanics" course for the geological engineering major. Starting from the current situation of course teaching, it gradually delves into specific teaching paths, aiming to optimize the teaching process, improve teaching quality, and cultivate high-quality geological professionals with good comprehensive literacy.

Bosong Ding, Ping Lou, Can Huang et al.

An improved method tailored for anisotropic soft soils is presented, integrating theoretical models and field data to calculate the grouting quantity required for tunnel foundations. Given the complexities of soil interactions, particularly under variable geological conditions, this approach incorporates nonlinear behaviors and empirical field data to improve accuracy. Our findings reveal that integrating these theoretical frameworks significantly enhances the understanding of stress–strain behavior during grouting, enabling precise calculations of both axial and vertical expansion. Validation against numerical simulations demonstrates the model’s reliability, highlighting the influence of soil types and grouting depths on expansion dynamics. This method not only helps mitigate risks in tunnel construction but also enhances foundation reinforcement strategies, driving progress in geotechnical engineering. It is particularly valuable for urban tunnel projects in complex geological conditions, where ensuring ground stability and safety is crucial.

NIU Zihao 1, 2, ZHU Zhende 3, QUE Xiangcheng 3, XIE Xinghua 4, JIN Kai 1, 2

With the construction and commissioning of major hydropower projects represented by Baihetan of Jinsha River, it is of great significance to clarify the mechanical and seepage characteristics of engineering rock mass under complex stress environment with high confining pressure and high water pressure. Based on the field survey data and the structural characteristics of the columnar jointed basalt of dam foundation, two kinds of columnar joint similar material model samples with different dip angles β, quadrangular prisms and hexagonal prisms, are prepared, and the true triaxial stress-seepage coupling tests are carried out. The test results show that the columnar jointed rock mass with different cross-section characteristics has strong permeability anisotropy, and the permeability coefficient k is positively correlated with β at different loading stages. During the true triaxial loading process, the volume strain εV of the sample can be used as an effective characterization parameter of k. At the volume compression stage, k shows a low level, and at the volume expansion stage k shows a rapid growth trend. The final failure mode of the samples exhibits three typical forms, and the most dangerous failure mode is the structural failure dominated by the shear slip failure of the joint surface, which mainly occurs in the samples with β=45°, 60°. Correspondingly, the lateral support of this kind of rock mass should be strengthened in the construction design of surrounding rock of tunnels and rock mass of dam foundation.

Yu Tan, Guangping Zhou, Huyuan Zhang et al.

Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater, providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository. Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater, and was used to hydrate the blocks during the swelling pressure and swelling strain measurements, as Beishan is the most promising site for China's repository. Healing of the surface cracks was recorded by photography, and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks. The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater, but not affected by the drying cracks. The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks. The maximum swelling pressure measured in strong (i.e. high ion strength) Beishan groundwater was 44% of the pressure measured in deionized (DI) water, and the maximum swelling strain was reduced to 23% of the strain measured in DI water. Nevertheless, the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks, as demonstrated by the pictures of surface cracks and CT images. The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable (3.7× higher) to the hydraulic conductivity of the fresh block, indicating the self-healing of drying cracks after hydration and swelling in groundwater. A simplified method of protecting the block with plastic wraps before installation is recommended, since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.

Daxing WANG, Haiyan HU, Jiaqun ZOU et al.

Objective To explore the enrichment conditions and main controlling factors of shale gas in the Lower Wuerhe Formation of the Permian System in the Junggar Basin, the Lower Wuerhe Formation in the Dongdaohaizi Sag was selected as the research object. Methods Based on the data of outcrop, core, well logging, well-calibrated seismic reflections and the technologies of total organic carbon (TOC) content determination, whole-rock X-ray diffraction, gas adsorption (N2, CO2), the distribution characteristics, organic matter development characteristics, reservoir characteristics, and gas bearing characteristics of the Lower Wuerhe Formation shale were studied. Results The results show that: (1) The organic matter of the Lower Wuerhe Formation shale is dominated by Ⅱ2 and Ⅲ types and shows an average TOC content of 1.58%. The average vitrinite reflectance (Ro) of organic matter is 1.46%, which indicates the mature stage. The average thickness of the source rock is 75 m. Summarily, the source rock is good and has a high gas potential. The basin simulation results show an average shale gas content of 1.89 m3/t in the Lower Wuerhe Formation. (2) The pores and microfractures in shale reservoirs are highly developed, and gas is primarily adsorbed in micropores and mesopores. The average porosity and permeability are 6.10% and 0.27×10-3 μm2 respectively, which are favourable for shale gas accumulation. (3) The shale has a high clay mineral content, with an average of 29.6%, providing a significant specific surface area and enhancing the gas adsorption capacity of the shale. Additionally, the average brittle mineral content is 50.9%, indicating good frackability. (4) Moreover, the shale reservoir exhibits a relatively large pressure coefficient of 1.58, indicating the favourable conservation conditions. The analysis of the regional tectonic-sedimentary environment and geochemical parameters indicates that the main factors controlling shale gas accumulation in the Lower Wuerhe Formation of the Dongdaohaizi Sag are geochemical parameters and preservation conditions. The key factors influencing shale gas accumulation include the high thermal evolution maturity of organic matter, large shale thickness, high TOC content, and good preservation conditions. These conditions suggest that the favourable area for shale gas exploration and development in the Dongdaohaizi Sag is located in the northeastern slope area of the sag's abdomen. Conclusion The results of this research reveal the enrichment conditions and main controlling factors of shale gas in the Lower Wuerhe Formation in the Dongdaohaizi Sag, which has reference value for deep oil and gas exploration in the abdominal area of the Junggar Basin.

Shubhadip Dasgupta, Satwik Pate, Divya Rathore et al.

This study investigated the use of portable X-ray fluorescence (PXRF) spectrometry and soil image analysis for rapid soil fertility assessment, with a focus on key indicators such as available boron (B), organic carbon (OC), available manganese (Mn), available sulfur (S), and the sulfur availability index (SAI). A total of 1,133 soil samples from diverse agro-climatic zones in Eastern India were analyzed. The research integrated color and texture features from microscopic soil images, PXRF data, and auxiliary soil variables (AVs) using a Random Forest model. Results showed that combining image features (IFs) with AVs significantly improved prediction accuracy for available B (R2 = 0.80) and OC (R2 = 0.88). A data fusion approach, incorporating IFs, AVs, and PXRF data, further enhanced predictions for available Mn and SAI, with R2 values of 0.72 and 0.70, respectively. The study highlights the potential of integrating these technologies to offer rapid, cost-effective soil testing methods, paving the way for more advanced predictive models and a deeper understanding of soil fertility. Future work should explore the application of deep learning models on a larger dataset, incorporating soils from a wider range of agro-climatic zones under field conditions.

Gabriel Zarzoso, Eduardo Roque, Francisco Montero-Chacón et al.

An FFT based method is proposed to simulate chemo-mechanical problems at the microscale including fracture, specially suited to predict crack formation during the intercalation process in batteries. The method involves three fields fully coupled, concentration, deformation gradient and damage. The mechanical problem is set in a finite strain framework and solved using Fourier Galerkin for non-linear problems in finite strains. The damage is modeled with Phase Field Fracture using a stress driving force. This problem is solved in Fourier space using conjugate gradient with an ad-hoc preconditioner. The chemical problem is modeled with the second Fick's law and physically based chemical potentials, is integrated using backward Euler and is solved by Newton-Raphson combined with a conjugate gradient solver. Buffer layers are introduced to break the periodicity and emulate Neumann boundary conditions for incoming mass flux. The framework is validated against Finite Elements the results of both methods are very close in all the cases. Finally, the framework is used to simulate the fracture of active particles of graphite during ion intercalation. The method is able to solve large problems at a reduced computational cost and reproduces the shape of the cracks observed in real particles.

Hernán Gustavo Solari, Mario Alberto Natiello

In Part I we constructed the Quantum Mechanics of a charged unitary entity and prescribed the form in which such a particle interacts with other charged particles and matter in general. In this second part we extend the description to the hydrogen atom testing the correctness and accuracy of the general description. The relation between electron and proton in the atom is described systematically in a construction that is free from analogies or ad-hoc derivations and it supersedes conventional Quantum Mechanics (whose equations linked to measurements can be recovered). We briefly discuss why the concept of isolation built in Schrödinger's time evolution is not acceptable and how it immediately results in the well known measurement paradoxes of quantum mechanics. We also discuss the epistemic grounds of the development as well as those of conventional Quantum Mechanics.

Zheng Wan, Jie Qin, Zhao Wei

On the basis of systematically sorting out the potential risk sources of underground structure construction, this paper describes the surrounding medium of underground structure as soil mass and rock mass. The main risk source of the underground structure based on soil medium comes from the construction mechanics analysis in the construction stage, and the leading factor of the underground structure loading in the construction stage is the stress-strain relationship of soil based on the unloading path. The deep underground engineering structure is faced with a series of disasters such as high-strength water gushing, high-strength rock burst, large deformation of soft rock, boulder collapse and rock burst under the action of unloading. In view of the unloading paths faced by the above two different media, the corresponding physical models are developed to describe the above phenomena according to their respective disaster evolution mechanism and disaster breeding mechanism, and the corresponding indexes required for the safety of engineering structures are obtained by solving the physical equations. According to the above indicators, the engineering structure and surrounding media in the construction process are monitored accordingly, and the feedback of the monitoring data is used to obtain the risk assessment and modify the current construction sequence, so as to provide a reference for better serving the construction safety of underground engineering structures. Citation: Wan Z

FENG Zhong-ju, WANG Si-qi, WANG Xi-qing et al.

High-fill culverts placed in valley topography have a complex earth pressure distribution law due to their locations around culverts in various valley topography conditions. In order to investigate the influence of valley topography on the earth pressure around the culvert of high-fill arch culverts, an interaction model of "topography-culvert-fill" was established by using centrifugal model test and numerical simulation method. Additionally, the distribution laws of earth pressure around the arch culverts and earth pressure concentration coefficient Ks at the top of the culvert under different valley widths B and valley slopes α were analyzed and were compared with the latest Chinese culvert design code. Furthermore, the mechanism of earth pressure formation of high-fill arch culverts under valley topography was presented. The research findings are as follows: (1) The influence of the valley width B on the earth pressure concentration coefficient Ks at the top of the culvert is significant, and the increment of the earth pressure concentration coefficient Ks at the top of the culvert is larger when B is 4D−6D（D is the clear span of arch culvert）. (2) When B is less than 4D, the topography would play the role of load reduction to the culvert. (3) With valley slopes ranging from 45° to 60°, the earth pressure at the tops and Ks would be affected dramatically. (4) When fill height is 20 m with α >70°, Ks≤1; and when 40 m fill height with α >50°, Ks≤1. (5) The Ks recommended by the latest Chinese culvert design code differs to some extent from those by centrifugal model test and numerical simulation. In the case of α =45° with a small B value, the earth pressure concentration coefficient Ks at the top of a culvert of the code is more conservative. (6) Ks of high-fill arch culvert in valley is related to the formation of arch top compaction area and isobaric surface. The arch top compaction area can cause the earth pressure concentration on the top of the arch culvert, and cause the vertical earth pressure of the soil around the compaction area to be arched. At a certain depth approaching the surface of the fill, the arch distribution gradually transits to the horizontal distribution, thus forming an isobaric surface. The upper load of the isobaric surface will be dispersed on the valley slope, so the unloading effect of the valley topography can be exerted.

HONG Zequn 1, SHI Rongjian 1, YUE Fengtian 1, HAN Lei 2

The temperature field is the basis for assessing the mechanical state and water-sealing performance of the frozen wall, which is an important research direction of the artificial freezing theory. For the freezing pipes in the form of a closed circumferential arrangement, there are only analytical solutions under regular annular conditions, including single-circle and double-circle models. However, the rectangular arrangement of freezing pipes is also very common in practical projects, especially for the subway station projects that use frozen concealed excavation, and the temperature field has not yet been answered. According to the geometric consistency of rectangular and annular layouts, based on the four-pipe model, a method of "replacing squares with circles" is firstly proposed for the rectangular problem. Furthermore, considering the boundary separable properties of the steady-state heat conduction control equation and the superposition principle of potential functions, the analytical solutions of the temperature field for rectangular arrangement with eight pipes and the generalized rectangular arrangement with multiple pipes are solved. By comparing with the transient numerical results the model test ones, the correctness and the applicability of the analytical solutions are verified. The results show that the temperature field exhibits a highly rectangular distribution characteristic near the pipe layout line, and the isotherm gradually transforms to a circular shape as it moves away from the freezing pipes. The inner side of the rectangular freezing wall develops faster than the outer side, and the temperature field inside and outside the 0℃ line is significantly affected. The influences of the freezing pipe arrangement on the geometric characteristics of the freezing wall should be reasonably considered in the design of freezing scheme.

Ковалев Дмитрий Петрович, Ковалев Петр Дмитриевич, Зарочинцев Виталий Сергеевич et al.

Рассматриваются результаты изучения длинноволновых движений с периодами более 20 ч на шельфе юго-западного побережья о. Сахалин с использованием полученных в натурных экспериментах временных серий колебаний уровня моря с дискретностью 1 с и продолжительностью от 4 до 6 мес. Спектральный анализ временных серий колебаний уровня моря для диапазона периодов от 8 до 200 ч выявил наличие длинноволновых процессов с периодами от 26.1 до 46.7 ч, которые значительно превышают инерционный период 16.48 ч. Численное моделирование шельфовых волн для экспоненциально выпуклых профилей морского дна, проведенное с использованием дисперсионного соотношения В.Т. Бухвальда и Дж.К. Адамса для волн континентального шельфа, показало, что обнаруженные волновые процессы с периодами от 31.2 ч до 46.7 ч являются шельфовыми волнами. Их амплитуды увеличиваются во время штормов; показана возможность передачи энергии от атмосферных возмущений шельфовым волнам, которые вносят вклад в формирование уровня моря, что подтверждает ранее сделанное предположение. Путем расчета разности фаз шельфовых волн на расстоянии 12.4 км между Невельском и Горнозаводском, наблюдаемых и определенных по теоретической модели, установлено, что вторая мода шельфовой волны с частотой 0.152 цикл/ч близка к теоретической. Регистрируемая в Ильинском и Горнозаводске волна с периодом 26.1 ч при расстоянии между пунктами 173.6 км не может быть шельфовой, а является волной Кельвина. Это подтверждено рассчитанной дисперсионной диаграммой, согласно которой длина волны около 689 км хорошо соответствует разности фаз для расстояния Ильинский–Горнозаводск. Установлено, что шельфовые волны, одним из механизмов генерации которых является напряжение ветра вдоль берега, имеют разные амплитуды в летнее и зимнее время, что обусловлено сезонным направлением вдольберегового ветра. В летний период направления распространения шельфовых волн и ветра противоположны, что ослабляет шельфовые волны.

علی غلامعلی زاده, نسرین قربان زاده, محمد باقر فرهنگی et al.

سابقه و هدف: هدررفت فسفر از اراضی کشاورزی و ورود آن به منابع آبی سبب پدیده سرشارسازی و شکوفایی جلبکی شده و کنترل فسفر ورودی به زیست‌بوم‌های آبی را به چالشی مهم برای مدیریت این منابع تبدیل کرده است. آزمون جلبکی به عنوان قابل اعتمادترین روش برای کمی‌سازی پتانسیل زیست‌فراهمی فسفر محسوب می‌شود. این پژوهش با هدف بررسی زیست‌فراهمی فسفر در سه نمونه خاک شالیزاری و ارتباط آن با رشد ریزجلبک کلرلا انجام گرفت. مواد و روش‌ها: نمونه‌برداری خاک از عمق 10-0 سانتی‌متری اراضی شالیزاری واقع در پنج منطقه پسیخان، پیربازار، سیاه درویشان، فخب و لاکان انجام شد. این اراضی برای مدت طولانی و به صورت سالانه کود فسفری دریافت کرده بودند. ابتدا با عصاره‌گیری پی در پی به روش هدلی بخش‌های مختلف فسفر در 5 نمونه خاک تعیین شد و سپس با توجه به مقدار فسفر کل، فسفر در بخش‌های مختلف و درصد رس، سه نمونه از خاک‌ها (پسیخان، پیربازار و لاکان) به عنوان تنها منبع فسفر به محیط کشت ریزجلبک کلرلا اضافه شدند. آزمایش در قالب طرح کاملاً تصادفی به روش اندازه‌های تکرار شده در زمان با سه تکرار انجام شد. مقدار کلروفیل a، تعداد سلول‌های ریزجلبک، فسفر کل محلول و فسفر ذره‌ای در روزهای صفر، 7، 14، 21 و 28 انکوباسیون اندازه-گیری شد. یافته‌ها: دو خاک پیربازار و فخب از نظر بخش‌بندی فسفر مشابه و ترتیب بخش‌ها به صورت اکسیدی< باقی‌مانده< کربناتی< محلول-تبادلی بود. در حالی‌که در سه خاک دیگر بخش‌بندی فسفر به صورت باقی‌مانده< اکسیدی<کربناتی< محلول-تبادلی بود. مقدار کلروفیل a ریزجلبک در هر سه نمونه خاک روند افزایشی نشان داد و در روز چهاردهم به بیشترین مقدار رسید و پس از آن ثابت شد. تعداد سلول‌های ریزجلبک در تیمار خاک پیربازار تا روز چهاردهم انکوباسیون و در خاک‌های لاکان و پسیخان تا پایان دوره انکوباسیون روند افزایشی نشان داد. فسفر کل محلول در تمامی تیمارها در طول دوره انکوباسیون تا روز هفتم روند افزایشی داشت و پس از آن کاهش یافت. فسفر ذره‌ای در روز هفتم انکوباسیون به شدت کاهش و سپس در ادامه انکوباسیون افزایش نشان داد. مقدار کلروفیل a و تعداد سلول‌های ریزجلبک در دو هفته اول انکوباسیون همبستگی مثبت و معناداری با فسفر کل محلول نشان دادند و در دو هفته بعد رشد ریزجلبک تحت تاثیر فسفر ذره‌ای قرار گرفت. نتیجه‌گیری: از آن‌جا ‌که خاک می‌تواند به عنوان منبع فسفر امکان رشد ریزجلبک را فراهم نماید، بنابراین توجه به فسفر ورودی به زیست‌بوم‌های آبی از طریق اراضی کشاورزی حاشیه رودخانه‌ها برای مدیریت پدیده سرشارسازی در تالاب انزلی ضروری است.

Erich Saurer, Albert Greinmeister

In the process of designing the construction of the S-LINK, soil investigations are currently in progress in the project area from Salzburg Central Station via Mirabell Square, “Mozartsteg” (Mozart Bridge) and further towards “Salz-burg-Süd” (southern district of the city of Salzburg). The soil investigation measures applied consider the boundary conditions of the Salzburg underground. This paper summarises the exploration methods and presents the most important results relevant to geotechnical engineering and tunnel construction. This includes results of direct and indirect explorations and of laboratory tests as well as their comparison regarding the derivation of parameters for the numerical modelling, which are provided to the general designer as a basis.

E. Eslami, Karolan Tremblay, M. Seifaddini et al.