Study On The Probability Statistics Of The Landslide Pressure And Mechanical Properties Of The Passive Flexible Protection Under The Action Of Landslide Accumulation

China is a country with multiple geological disasters, especially in the Midwest, the terrain slopes precipitously, the geological structure is complex, the rock and soil is crushing, the catastrophic climate condition is remarkable, which cause the landslide disasters to occur frequently, and serious threat to the safety of people’s lives and property.At present, many kinds of landslide disaster prevention are applied in engineering practice, as the unique advantages of the passive flexible protection in the aspects of safety, economy, applicability and environmental protection, the application of passive flexible protection, in the prevention and control of slow speed accumulation soil landslide, is more and more widely. However, the structure design of passive flexible protection and related research are more concentrated in the dynamic response of passive flexible protection under the rock-fall impact, while research on the prevention of landslide by passive flexible protection is few. The value of the landslide accumulation load directly influences the structure design of the passive flexible protection, and then decides the protective effect of the protective structure. In addition, the standard configuration of passive flexible protection is based on the rock-fall impact test data, so the protective structure needs to be adjusted to prevent the landslide disaster.In order to improve the application of passive flexible protection in the prevention and control of landslide disaster, theoretical analysis and numerical simulation are used in this paper, The load value of accumulation, the mechanical performance and structure design of passive flexible protection are studied, The main research contents are as follows:(1) The limit capacity of landslide and the calculation method of landslide pressure are studied. Calculation diagram of the accumulation capacity of passive flexible protection for landslide is established, the calculation formula of the limit protection capacity of the passive flexible protection is determined, and the influence of accumulation body slope angle, slope angle, the installation angle, the height and the length of the passive flexible protection on the limit protection capacity is analyzed. Then, the calculation formula of landslide pressure is established. Analysis results show that the landslide volume is determined by the slope angle of landslide behind passive flexible protection; The landslide pressure of passive flexible protection fully covering with landslide is underestimated as thinking the angle of repose is equal to the internal friction angle; The installation angle is often 90 degrees when passive flexible protection is applied to protect the slow moving accumulation landslide.(2) Based on probability theory, mathematical statistics and structural reliability analysis methods, the landslide pressure is calculated. According to a potential landslide in the lion Liang Mountain of "5.12" Wenchuan earthquake, the investigation and statistical analysis of landslide pressure were carried out. A load model of accumulation body is established. The average value, standard deviation and coefficient of variation of the load sample are determined. The approximate expression of probability density function and probability distribution function are derived by the K-S test method; Based on the principle of engineering structure reliability calculation, the standard value of landslide pressure of passive flexible protection is presented, which satisfies the 95% guaranteed rate. Calculation results show that the average value and standard deviation of the load sample of the potential landslide in the lion Liang Mountain are 45.25 kN/m2 and 1.363 kN/m2 respectively; The value of landslide pressure conforms to the extreme value type I distribution; the standard value of landslide pressure of passive flexible protection which satisfies the 95% guaranteed rate is 47.50 kN/m2.(3) The impact dynamic calculation model of rock-fall and static loading calculation model by numerical method were established respectively, to analysis the mechanical behaviors of passive flexible protection with different connection mode between steel column and wire rope or steel column and foundation. Due to the standard configuration of passive flexible protection being used to protect a certain impact kinetic energy of rock-fall hazards, moreover, compared with the impact force, the accumulation body load can be regarded as the static load, and mechanical behaviors of passive flexible protection can be quite different. Therefore, based on the results of numerical analysis, the program design of passive flexible protection used to protect rock-fall for the purpose of protecting landslide disaster was researched, and the component adjustment suggestions were gave. Analysis results show that the connection mode of two-hinged between steel column and wire rope or steel column and foundation is suggested under the action of dynamic or static load; Based on the standard configuration of passive flexible protection, the relative section area of the pulling anchor rope or the supporting rope should be raised, and the bending rigidity of the steel column should be raised.