| The characteristics of the geotechnical engineering of Junyao Plaza directly affect the safety of the entire project.Therefore,it is of great engineering significance to carry out indepth research.On the basis of the analysis of the engineering geological conditions of Junyao Plaza,the author takes the geotechnical quality evaluation of the site as the research focus,and conducts detailed investigation and analysis on the geotechnical characteristics,geotechnical structure and dissolved rock mass of the site,and finally to Jun Yao Whether the foundation soil of the square meets the requirements for the use of the building foundation.The specific research contents and results are summarized as follows:(1)Conduct a detailed investigation of the geotechnical geological conditions of the site.No traces of the fault activity since the Holocene affecting the safety of the proposed building have been found in or near the site.There is no evidence of new tectonic movement in the cover.According to the drilling,the foundation soil of the site of Junyao Square is composed of artificial fill layer and Quaternary alluvium.The basement rock is the bedrock of the Baijishan Formation of the Early Cretaceous,and the depth of the rock is different.The comprehensive section of engineering geology is divided into 7 layers of the main layer.According to the geotechnical engineering geological conditions of the Junyao Plaza area,it is recommended that the proposed building adopt a pile foundation,and the pile type adopts punching and rotating piles.(2)During the study period,sufficient exploration and indoor tests were carried out.In order to determine the stratum structure and the deformation characteristics and strength characteristics of the foundation rock and soil,the relevant physical and mechanical parameter data were obtained.(3)Evaluation of geotechnical quality of site foundation According to the degree of dissolution of rock mass,the quality type of foundation rock is divided on site.The site of Junyao Plaza is in the relatively stable area of geological structure,which is a basic stable foundation.The geotechnical geological conditions are general.The lithology of the site rock is mainly argillaceous siltstone.The bedrock is buried in different depths,uneven weathering,and varies greatly in the horizontal and vertical directions.The uniformity of the pile foundation bearing layer is poor.During engineering design and construction,it should be ensured that the pile foundation enters the designed weathered rock belt.At the same time,reasonable and safe measures should be taken to avoid the quality accident of the pile body skew and broken pile.The foundation of Junyao Plaza is uneven foundation and the deformation characteristics of the foundation Mainly for differential settlement and tilt.The overall evaluation of Junyao Plaza is in a relatively stable geological structure,which is a basic stable foundation.The geotechnical engineering geological conditions are general.Under the premise of taking into account the unfavorable geological factors and special geotechnical conditions,and taking corresponding measures,it is suitable for the construction of this project.(4)The foundation soil of the site is mainly filled,the Quaternary alluvial layer,the horizon is relatively simple,but the state,depth and thickness of each rock layer vary locally in the horizontal and vertical directions,and the mechanical properties of the soil layer are discrete.Large,high compressibility foundation,and large difference in compression modulus,so the uniformity of the foundation is poor,stress concentration or stress diffusion occurs under load,resulting in uneven settlement of the foundation,affecting stability.(5)Thicker artificial fill and silt soil are prone to large settlement or uneven settlement before untreated,and negative frictional resistance will be generated to the pile foundation.The negative frictional resistance above neutral point should be formed.The load is used as part of the external load to check the bearing capacity of the pile foundation,and corresponding measures can be taken to reduce the negative frictional resistance.The weathered rock in the site has different burial depths,strong weathering,uneven weathering,and large fluctuations in the bedrock surface and weathering boundary.It has adverse effects on the uniformity and stability of the foundation and the construction of precast piles.The weathered rock softens and loses water.Water disintegration,so disturbances to weathered rock should be minimized. |
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