Microscopy Observation of Samosir Formation Paleosoil, Tuktuk Sidaong, North Sumatera, Indonesia.

Samosir is the islands that emerge and standing upon on Toba Caldera after it’s the last eruption at 74.000 years ago. Samosir Island known as the caldera floor that uplifts parallel with Toba’s caldera flooding. In this study, we have observed an outcrop in Tumutuk, Samosir Island that hypothesized as a lacustrine deposit, and we found a paleosoil layer that might give more answers about the geological process in this area at the past time. Based on this outcrop, we described it, followed to measure its stratigraphy section, and took representative samples from the paleosoil layer, then observed the samples under the stereo-microscope as polish rock section, in normal light & negative images. As the result we identify several features of paleosoil & its sedimentary grain that shown this paleosoil layer, two events of the volcanoclastic deposits flown, and exposed two-time, and forming soil, it may form in the shallow swamp in a lacustrine environment, coincide with caldera flooding and caldera floor uplift event.

Image Classification Recognition for Rock Micro-Thin Section Based on Probabilistic Neural Networks

In order to implement the recognition automation of rock section pore images, a method combined K-means clustering with probabilistic neural network is proposed and applied to rock thin section images. Firstly, K-means clustering is used as segmentation algorithm, the rock images are divided into two types and extracted enough features and it is shown good classification recognition effect on testing dataset. Secondly, 100 pieces of rock image section are used as validation dataset, including 20 groups, each group has 5 images and 200 data samplings. Experiments show that the probabilistic neural network can be used as rock texture classifier, the average correct classification rate is around 95.12%, which can meet the practical application needs.

Rock Image Pore Identification Based on Fuzzy C-Means Clustering and Neural Networks

In order to realize the recognition automation of rock section pore images, a method combined Fuzzy C-Means clustering with BP neural network is proposed to recognize the pore of rock images. Firstly, Fuzzy C-Means clustering as segmentation algorithm are applied to the rock images and they are divided into two types, then using the BP neural network training and classification recognition. It is shown that the trained BP neural network can accurately identify the effective porosity in the casting image, and lay a good foundation for practical applications.

Rock Classification Based on Image Processing and Neural Networks

For the identification complexity of rock microstructure, based on numerical analysis of rock section images, an automatic rock texture classification method and identification system is proposed in this paper. Digital grey image processing of rock thin section is used for features extraction, the features are then as inputs to the neural network model, the model output is the rock microstructure classification. 100 pieces of rock section images from Sulige region in Changqing Oilfield are used for the experiment; the whole dataset is randomly divided into 70 images for training datasets, 15 images for validation datasets and 15 images for testing datasets. It is shown that the correct classification rate for automatic identification of rock microstructure is about 93.3%. Therefore, the proposed method for solving geological problem is effective and can get a good identification performance for rock microstructure classification quickly and accurately.

Research and Design Optimization of Canceling Setting Invert in Road Tunnel

Use FLAC 3D finite difference software for numerical simulation and static calculation of the different models. Study the deformation and forces condition of different model during the process of excavation. The results show that setting invert of highway tunnel in Ⅳ1-grade rock section can improve the stress state of the supporting structure and reduce the surrounding rock deformation effectively. At the same time, the flat bottom tunnel applying C25 concrete and grouting bolts could improve the integrity of surrounding rock below the tunnel sidewall. It is can be considered to cancel the setting of invert to achieve the purpose of simplifying the construction and design.

Mechanics Analysis of Grade V Surrounding Rock Primary Support in Maanziliang Tunnel

Commonly used finite element strength reduction to calculate the safety factor of slope，to analyze the stability of the slope[1～3]. Recently it also proposed the methods to evaluate the safety factor for the stability of surrounding rock of underground chambers and supporting structural mechanics[4～6]. For Qinling Mountains of the complex geological conditions in the Maanziliang highway tunnel, this article use the finite element method from the bolt resist tension, bolt length, the force of sprayed layer of concrete to computing gradeⅤsurrounding rock section of primary support safety factor, to give evaluation to support mechanics of the Maanziliang tunnel.

Research on the Bearing Capacity for Rock Bolt Crane Girder in the Underground Powerhouse of Large Hydropower Station

In this paper, according to the reality that there is no mature Chinese national design criterion but partial enterprise standard for rock bolt crane girder in the underground powerhouse of large hydropower station up to now. Based on the geological conditions, the rock bolt crane girder was designed by using method of rigid body equilibrium. The reinforced anchoring measures for rock bolt crane girder in undesirable geology were studied subsequently by the experience of analogous projects. The stability of rock bolt crane girder in underground powerhouse was analyzed and evaluated by Finite Element Method (FEM). Then the bearing capacity of crane beam was researched by means of bearing testing. The results show FEM is practicable to evaluate the stability of the rock bolt crane girder and to guide the rock bolt crane girder designing. The results also show the reinforced anchoring measures are appropriate to displace the undesirable surrounding rock section by using concrete. The results of bearing testing show that the design of rock bolt crane girder and its anchoring measures are rational, and crane girder can meet to the requirement of safe operation.