Study On Mechanism And Optimal Design Of Pile And Anchor Bolt In Rock Slope Engineering

Slope is important environment for mankind and an important component of engineering construction. The surface of lithosphere can be inevitably transformed in the course of the production and construction of human beings. Specially, many human being engineering activities such as rebuilding high way and constructing cities in mountain area often cause so many rock slope. Minimuming the load and forecasting the safety degree and the critical state are the common study focus for geologists and engineers whether it is road or railway, dam base. The design is very important if slope is steep and safety degree can't be overlooked. Or slope design is tightly connected with engineering expense.Two methods are used all the way for the design to harness rock slope. The methods are anchoring and retaining. The anchoring measure is anchoring bolt and the retaining measure is slide-resistant pile. It is an aim to study the mechanism and the optimum design of anchoring bolt and slide-resistant pile in harnessing rock slope in the paper. The major content is demonstrated from two sides in the paper. Firstly, anchoring mechanism and orthogonal and optimum design of anchoring bolt are demonstrated. Secondly, the formal mechanism between pile and soil of slide-resistant pile, the calculating methods and the optimum design of its system are demonstrated. The mechanism and the optimum design of anchoring bolt and slide-resistant pile are demonstrated on the base of two engineering examples in the paper. The two examples are high way slope and city slope in Three Gorges. The conclusions are as follows:1.The parameters of anchoring bolt are very important for anchoring effects. The length and the interval of anchoring bolt are main parameters and must be decided in engineering design. Study shows that the effect of anchoring will be greatly reduced if its length is too long. So, selecting its length is very significant to fully play its role and get economical and rational anchoring result. 2.Anchoring parameters of slope of Dawu section in Jingzhu high way are best selected using orthogonal design principle. The results show that the effects of anchoring parameters are different and remarkable according to horizontal deformation of slope. The order of the difference is : the effect of anchoring bolt length > the interval of anchoring bolt > thickness of sprayed concrete. The optimum parameters are obtained. They are: its length is 3m, its interval is 2m and the thickness of concrete is 100mm.3.Slide-resistant pile bears down-sliding force that slide mass generates. One part is transferred to stable stratum under the sliding plane through pile. The other is transferred to slide mass in front of the pile.4.The designed thrust is greater than the thrust difference P where pile is placed. In fact, the designed thrust is P/(1-ξ) because one part of P is transferred down.. The 'ξ' is transferringcoefficient and it is between 0 and 1. ξ is decided according experience analogy method if there are no test data.5.The anchoring depth of slide-resistant pile theoretically is decided according to permissible sided compressive strength of stratum and permissible bearing load of the base of pile. Commonly, it is decided according to permissible sided compressive strength of rock stratum in the side of pile. The formula of anchoring depth is established using the principles that sided stress of stiff pile must abide by. The formula is or .6. For scattered piles, thrust is transferred to slide-resistant pile through soil arch between piles. Then, the thrust is transferred to stable stratum through pile. The formula of pile interval is obtained by structure mechanics: .7.Decision of more accurate direction of thrust is random because of concealed underground engineering. In view of it, slide-resistant pile whose section is round is exploited in harnessing slope. For slide-resistant pile whose section is round, more accurate direction of thrust isn't necessary. Thus, its construction is convenient...