| The anchor at the end of the nineteenth Century first used in coal mine roadway, mining rock reinforcement, with the rapid development it's now the most important part of modern coal roadway, deep within the strata, anchorage depth, the lower strata in the upper strata anchorage stability, and prestress active supporting surrounding rock to fully mobilize the deep surrounding rock strength, has a good supporting effect. Now anchor bolt is not only used in mine coal mine, but also used in engineering technology, and it is applied to the foundation pit, slope, dam and so on.Since the bolting support in the last century, the anchorage technology has been developed rapidly in the last decades. In the urban construction, a large number of application in the deep foundation pit support. In recent years, with the profoundly use of anchor in the field of engineering, it has been developed many different anchoring technology, but there is no denying that theoretical research on anchoring technology far missed its application rate.This paper discusses the commonly used in foundation pit based on the way, leads to tension dispersion type anchor in deep foundation of the stress mechanism of normal tension anchor and anchor tension dispersion type analysis, and we derive the anchor axial force and shear stress force distribution analysis solution, this on the basis of further parameters in the formula are analyzed, focusing on the cohesion, internal friction angle, Ea/Es stress distribution curve of influence. Finally, the dispersion of tension anchor application in Beijing Yaohui international city foundation, introduces its design idea, construction points and application prospect.Moreover, the foundation for a variety of reasons, from the foundation pit excavation completed to trough backfill, after more than two years of time, in such a long time, the slope and foundation pit surrounding non obvious cracks and deformation, the overall stability of foundation pit is good, fully shows that the tension dispersion type anchor is suitable, in technology is reliable; the rally dispersed anchor because of the amount of stainless steel wire for the whole project by more than 20%, reduce project cost, reduce the waste of social resources, has obvious economic and social benefits.And draw the following conclusions:(1) Anchor axial force and shear stress were increased with the internal friction angle and cohesion value, and the inner friction angle and cohesion of the larger, the distribution of axial force, shear stress is not uniform, and the Ea/Es curve rose more obvious; the larger, axial force, shear stress the force curve is flat, the lower section of the proximal anchorage stress level.(2) The shear stress distribution is uniform, the creep deformation is small, and the stress concentration phenomenon is greatly reduced, and the utilization rate of formation strength is high.(3) Dispersion type tensile bearing capacity of anchor and anchor length increase in proportion to the same length, bearing capacity than normal tension anchor can be increased by more than 30%, is suitable for the requirements of high bearing capacity in engineering; design should fully consider the formation and optimization of anchoring section and from the length, reasonably determine the grouping and stretch locking value, in order to make full use of the strength of rock and soil.(4) Compared with the ordinary tension type anchor bolt, the steel wire can be saved more than 20%, and the cost of other aspects is not increased, and the economic benefit is good.Based on the analysis of the tension dispersive-type anchor force mechanism and its application in practical engineering application, summarize the characteristics of direction tension dispersion type anchor high bearing capacity, excellent performance, strong adaptability and wide. |
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