The Study On The Values Of Different Properties Of The Gravel Soil Foundation Coefficient M Value By Model Test

Pile foundations often subjected to horizontal forces. The horizontal load capacity is the key factor which directly affects the safety and stability of pile foundation The bearing capacity of the laterally loaded piles is mainly controlled by the nature of the pile and the properties of the foundation soil. The coefficient of m of the horizontal resistance coefficient of the foundation soil is the physical parameter of the soil. It is a physical quantity to measure the horizontal resistance of foundation soil. It is also the parameter of calculating the horizontal bearing capacity of pile foundation. The properties of soil are the main factors influencing the m value, and the value of m is different in different soil and different design requirements.For grade a design requirements of building pile by static load test of single pile to obtain the mvalue, and the most general specification through building pile foundation engineering analogy and experience value is determined, so the m value is reasonable or not directly related to the level of the design of piles is reasonable.Transmission line tower appeared in southwest mountainous land based gravel up to carry out m value research based on gravel soil classification, properties of large differences, the standard value range, a comprehensive selection of arbitrariness.After consulting the literature, it is found that the compactness and the amount of stone are the two main factors that influence the properties of gravel soils. And the apparent m values of different characters are different under the pile-soil interaction. Study on the deficiency of the ultimate horizontal resistance of different characteristics of gravel soils foundation.This paper adopts the indoor physical simulation test method for different properties of gravel soils were apparent m value and intrinsic m value to design and carry out the change of gravel soil compactness, gravel content and pile widthsingle pile horizontal static load test and horizontal compression test model.Mainly got the following conclusions and cognition:?1? The apparent m value obtained from the horizontal static load test of single pile is the coefficient of foundation. The change of density had the most significant effect on the m value, followed by the stone content, but the change of the pile width had almost no influence on the m value. The value increased 1.83 times, the apparent m value increased by Dr, and the apparent m value of gravel soil base of Dr=60.0%was 175.61MN/m⁴. With the increase of P5 content, the apparent m value increased by 1.24 times, with an increase of.?2? Under the action of horizontal force, the critical load Hcr and the ultimate load Hu of pile foundation increases with the increase of Dr, the amount of P5 and the diameter of pile. The nature of the loose soil is the worst, and the displacement of pile top is the smallest. The deformation of the soil under high load is mainly caused by the dislocation between the coarse grains and the high content of the soil. The gravel soil with high stone content can be used to improve the bearing capacity of soil.?3?The m value is the bottom soil physical parameters directly affected by the properties of foundation soil, the relationship between the response of ground level of soil resistance and horizontal strain, compaction effect on the gravel soil intrinsicm value was the most significant, with the density of m increases significantly increased.The effect of soil engineering structure can not fully play its level of resistance, so that the m value is small, in the absence of the pile under horizontal compression can achieve the maximum value of the intrinsic m value. Comparing the m values obtained from the two tests, the intrinsic m value obtained by the horizontal compression load test is larger than the apparent m value, which can better reflect the horizontal resistance of the gravel soil. Generally, the intrinsic m value is 1.37 times larger than the apparent m value, and the m value of the different loading methods also has a big difference compared with the same pile width gravel foundation, the larger the m value is, the larger the amount of soil mass.?4?The gravelly soil foundation pile, soil displacement x and apparent m value showed exponential nonlinear relationship. Formula ism=b_m?x/B×10³?^-1.038,bm Breference table 5-5, The gravel soil foundation power index average value of kwas-1.038.?5? Double parameter method using composite stiffness principle analysis of the compactness of the single pile static load model test data analysis. The resistance coefficients of soil K with depth is non-linear,K=mz0.7.For all kinds of gravel soils are calculated in 1/n=0.7 when the most appropriate data The pile-soil stiffness ratio of pile stiffness should be small, between gravel soil pile and soil is negative form, a part of the pile is used as soil.