Applied Mechanics and Materials Vols. 438-439

Abstract: In the modification of narrow deep soil channels of early urban excavation, because of great depth and steep slope, the gravity retaining wall slope will be needed. The problems of soft soil subgrade treatment at channel bottom have to be solved. Combined with the old channel treatment project of a city, as practical example, the method by which the soft subgrade of channel retaining walls strengthening with pine piles, is described. By application of Coulomb Theory, the stability calculation for gravity pitch-up oblique retaining walls is conducted. The results show that using pine piles is a good method for strengthening the soft soil subgrade with small thickness below the water level.

Abstract: To take the natural differences of geotechnical materials into consideration, reliability analysis of slope stability with Monte-Carlo method was carried out on a slope of deep pit. The results show that Monte-Carlo method is equal to the limit equilibrium method, the most dangerous sliding surfaces matching the practice could be found according to the method introduced in this paper.

Abstract: Based on the analysis of geological data and meteorological data of landslide, the mechanism of rainfall-induced landslides was analyzed, and the relationship between landslide and rainfall was further discussed, including the landslides and rainfall distribution, the relationship between landslide and frequency of rainstorm, and the time relationship between landslide and rainfall. The results show that the probability of landslide occurrence and the quantity of landslides have positive correlation with rainfall. The landslides mainly occur from May to September in which the monthly mean rainfall is large. Meanwhile, landslide occurrence is closely related to the characteristics of rainfall of that day and rainfall of early days. When the daily rainfall exceeds 50mm or 10 days accumulative rainfall exceeds 100mm, the landslide is prone to occur and the occurrence rate of the latter is higher.

Abstract: Multistage discharge gentle slope combined with wide platform was adopted in the protection for high slope of highway in loess area, but vertical slope was often adopted at construction engineering of high slope as there was no enough site space for step-slope under the construction of urbanization in the western loess region of Henan province. A typical loess high slope in Lingbao city was taken to discuss the prevention measures for upright loess high slope. Design parameters for slope protection was given in detail, approach on the control plan for deformation has both excavation slope of 35m high and fill slope of 30m high. While reinforcement scheme of anchor cable plus stiffened-cylindrical was used in slope protection, the reinforced retaining wall was used to support the filling slope, in addition, loess slope management must be prepared to slope drainage design and construction.

Abstract: As lack of explicit analysis method on the sequence of many factors influencing the plastic zone extension of surrounding rock, the grey correlation analysis method is adopted to study the relationship between the plastic zone extension radius R_p and the six factors such as cohesive c, internal friction angle φ, deformation modulus E, unit weight γ, initial ground stress σ and the radius of chamber r. By dealing with dimensionless, the corresponding sequences composed with the sensitive factors as sub-sequence and the plastic zone extension radius as mother sequence are obtained. The gray correlation analysis model of sensitive factors which evaluates the results with grey correlation degree is built by the methods of dimensionless and extreme difference variation. Then, an engineering example is analyzed with grey correlation. Based on the analysis results, the sorting of sensitive factors is φ > σ > c > r > E > γ. It implies that the influences of internal friction angle φ and initial ground stress σ are the most prominent, and the sensitivities of deformation modulus E and unit weight γ are lowest. These are in good agreement with the analytical formula of classical theory, and can be used in guiding the further optimization and improvement of the analytical expression of the plastic zone extension radius R_p of surrounding rock.

Abstract: Dangerous rock masses in south of a city, once destroyed, it will be a threat to peoples lives and property in downstream. In this paper, distributions and morphological characteristics are analyzed on the basis of studying its geologic environment and precipitating factors of instability. And it quantitatively analyzes and valuates the stability of number 2 and 17 single dangerous rock by means of planar slide method and analysis of engineering geology respectively. Studies show that number 2 is in an unstable state and number 17 is in a stable state. Consequently, the controlling suggestions associated with practical situation of the project are presented.

Abstract: Finite element method was used to simulate the regularities of distribution and diversification about the landslide displacement, stress and strain of left dam shoulder of one reservoir in Tibet. The mechanism of slope deformation and failure was achieved through analyzing landslide stress field distribution and formation mechanism. Results show that stress concentration areas mainly lay in the tension stress zone, weak rock plasticity zone and shearing export sectors. The results provide some theory basis for the safe construction normal work and control of the reservoir.

Abstract: Due to the particularity of the ancient city wall, the collapse damage of ancient city wall earthen ruins is different from general soil slope failure. Through on-site observations and theoretical analysis, collapse failure process and mechanism of ancient city wall earthen sites under the action of capillary water is studied, and protection measures are proposed. Collapse failure process of earthen sites under the action of capillary water has the characteristics of particularity, diversity and stage. Capillary water reduces the stability of ancient city wall by changing the soil physical properties, chemical and ice split role. Finally, the effect of capillary water is illustrated through a specific project example.

Abstract: Kala Hydropower Station is located in the midstream of Yalong River in Sichuan Province of China, and the type of dam is concrete gravity dam, with a largest dam height of 129 m, an installed capacity of 1000 MW and a storage capacity of 255.8 million cubic meters. The slope on the right bank of the dam site is mainly composed of hard metasandstone and marbles interbedded with carbonaceous slates and the dip of rock formation is the same as the aspect of slope, so that it is a typical bedding slope. The field survey indicates that the failure of bedding slope of hard rock is not on a common mode of slipping-bending or buckling, but on an uncommon failure mode. The paper introduces a research method that starts with geologic history, analyzes current state and predicts the future failure mode, analyzes the characteristics and phenomenon of slope failure, and adopts the finite element calculation method to analyze the plastic zone resulting from slope deformation. According to the deformation evidence and calculation results, the engineering geologic mechanical theory is used to analyze the deformation and failure mode of slope, and it is indicated that the current and future failure modes of hard rock slope with large thickness are all slipping-shear failure.

Abstract: The stability of granular accumulation such as silt dyke is intimately related to stable slope angle. In this paper, the repose angles of granular medium of different mineral compositions, particle shapes, grain sizes and moisture contents were measured. The mechanical mechanism of granular slope stability was analyzed, as well as influence factors of stable slope angle. The results show that internal friction coefficient f is the key factor. For dry granule, form roughness and surface roughness are the main factors influencing f, leads to different rules of repose angles changing with mineral composition, particle shape, and grain size. With the increasing of moisture content, f increases, the repose angle increases at first, reaches the maximum and then keeps basically stable; the process is affected by the particle surface roughness, water film thickness, and adsorption capacity which is related to the mineral composition, particle shape, grain size of the granular medium.