In the considering problem usual tasks of designing ground dams (evaluation of filter strength, compressibility and ground permeability) are overlaid by new tasks, that have never touched upon earlier, that provide reliability of earth dams under extreme conditions and that are exposed by new additional forces such as intensive deformation and curvature of base. Here are dependences allowing determination of accepted values of earth surface deformation of ground dams on undermined territories. Using this methodology, you can compute required constructively technologic protection measures. Solution of such problems as predicting behavior and degree of reliability from external influence of a dam at given expected deformations, - can be brought into action. Prediction of conventional dams reliability may been carried out without underworking.

According to the authors the lack of evaluation methods for efficiency of pile behavior leads to an increased degree of randomness in the selection of type, material, shape and placement of piles, and, as a consequence, to overspending the material, energy, labor costs and, respectively, to more expensive construction. The work is devoted to the determination of the efficiency of piles of various cross-sectional forms (round, square, cross- shaped, T-shaped and double tee forms). A number of methods and criteria for quantitative evaluation of the efficiency of piles were proposed. Furthermore, the results of studies of the pile efficiency depending on the driving depth at the above-mentioned forms of cross-sections were given. Researches have shown that quantitative values of pile efficiency are approximately the same for the following forms for round and square cross-section; for T-shaped and double tee; and the are exactly the same for cross-shaped and T-shaped cross-section. Analysis of considered piles forms showed that maximum efficiency was achieved under the minimum depth of 2 meters, and then it gradually decreased. Also there was found an anomaly: at a depth of 10 meters the efficiency of cross sections with the tabs (III, IV, and V-shaped branchy) again begins to rise slowly. The results allow us to optimize more accurately the selection of the pile component in the foundation design

Abstract. This article provides estimates the parameters of protection from cracking dam due to volume compensation method. This article discusses the method of compensation dam volume. This method allows calculating the settings of security causing cracks the dam. Presents graphs of horizontal deformations of elongation calculated surface along the length of the construction and in time. Showing horizontal stress distribution diagram in the ground around the pile in plan and in section. Given all the necessary formulas for the method of compensation of the dam volume.

Abstract. The article presents the calculation of the limit depth of cracks in the dam, the calculation of step cracks in the dam, the calculation of full disclosure, the calculation of the direction of the cracks in the dam, the position of the first crack and their natural clogging. As well in this article has been shown all the necessary formulas for these calculations.

No abstract

Magazine of Civil Engineering, №4, 2012Булатов Г.Я., Гатанов Д.С. Надежность грунтовых плотин на сложных основаниях Надежность грунтовых плотин на сложных основаниях К.т.н., доцент Г.Я. Булатов; инженер Д.С. Гатанов*, ФГБОУ ВПО Санкт-Петербургский государственный политехнический университет Ключевые слова: надежность гидротехнических сооружений; трещинообразование; трещиностойкость; подработка территории; грунтовая плотина; деформации основания Вопросом надежности грунтовых плотин, в том числе и на сложном основании, занимались многие исследователи. Тем не менее, проблема защиты грунтовых плотин от опасного воздействия подземных горных работ остается достаточно сложной и малоизученной и по настоящее время. Это положение объяснятся как ее новизной, так и особенностями конструкций и условий работы данного типа сооружений: возможно возникновение трещин при наличии растягивающих напряжений в грунтах. Допущение же трещин ограниченных размеров, хотя принципиально и применимо в расчетах прочности грунтовых плотин, но до настоящего времени не имеет достаточно надежных решений.

No abstract

In connection with intense underground mining operations, not only industrial and civil buildings and structures, railroads, and pipelines but hydraulic structures as well --earth dams, reservoirs, and ash and sludge storage ponds --fall into the zone of influence of undermining.According to the existing standards all undermined structures should be protected from the harmful effect of undermining. To provide reliable operation of structures it is necessary to know the permissible values of the parameters of deformation of the foundation and in the case of exceeding the permissible deformations, to take various steps to eliminate possible failure of the structure.Failures of earth dams, as shown by the considerable experience of operating these structures, are associated with considerable material damage in connection with emptying the reservoir and flooding of nearby territories and with loss of life, and failures of dams of sludge storage ponds can lead to pollution of the environment [1][2][3]. it is impossible to forbid undermining of earth dams and dikes of reservoirs and ash and sludge storage ponds, since in this case it will be required to leave untouched large mineral resources located under them. This problem is completely new. It is of interest to examine the conditions under which hydraulic structures fail.Underground mining has one common important characteristic consisting of as a result of extracting minerals, cavities are formed in the rock mass which disturb the equilibrium of the surrounding rocks. This disturbance leads to their subsidence starting directly from the adjacent lower beds with subsequent development right up to the surface, which also experiences vertical and horizontal displacements and deformations. In this case the part of the surface subjected to the effect of mining operations is usually called the subsidence trough~ In the general case points of the surface and underlying layers have both vertical absolute movements (subsidences) and horizontal displacements (offsets) directed from the margins of the trough toward its center. The subsidence trough is usually also characterized by relative quantities, whereupon by horizontal elongation--compression strains e is meant the same as in hydraulic engineering, i.e., Sx = Al/l (Al is the increment (shortening) of the investigated area with length l). Nonuniform subsidences are denoted in terms of the slope i and curvature K = I/R = Ai/lav (Ai is the difference of slopes of two adjacent areas; lay is the average length of these same two areas). The vertical sections of the trough passing through points with maximum subsidences of the surface are called its principal sections. Central, flat, and marginal parts of the trough are distinguished according to the character of the distribution of the principal parameters. The character and regularity of the distribution of the principal parameters of subsidences along the length of the marginal part of the trough L were established on the basis of long-term on-site instrumental observations...