Study On Permeability Of Basalt Foundation With Pore Structure And Its Application

With the rapid development of urbanization in China,the increase in the degree of urban ground hardening,lead to the urban surface runoff has increased significantly.In cities where rainfall is high,the phenomenon of "city watching the sea" often occurs.At present,in basalt areas with penetrating properties,most of the drainage ditch use mortar and chipping stone for paving design and construction.Cracks in the rock are filled with clogging,reduces the permeability of basalt foundations.If unpaved drainage ditch,utilizing good permeability properties of basalt foundation,surface water can be guided to the ground with maximum efficiency.It not only can reduce the surface runoff of the city,also greatly increase the drainage capacity of side ditch and optimize the cross section form of drainage ditch.It's the primary important to find out the permeability of basalt foundations in the design study of unpaved drainage ditch.It can provide reference for future similar research and engineering problems.This paper relies on the "Research on the permeability and optimization design of volcanic rock areas based on the construction of a ‘Sponge City'" project to study and apply the permeability of basalt foundations fractures with pore structure.First,using acrylic parallel plates simulates rock cracks,and design rock fracture permeability testing devices.This device is used to perform the smooth parallel plate test.The results obtained are compared with the classic cubic formula to verify the reliability of the device for the fracture rock permeabil ity test.Second,according to the characteristics of the pore structure rocks,us e artificially drilled acrylic plates to simulate the pore structure basalt,and conduct model penetration test to explore the permeability of single fractures of pore struct ure basalt.Find out the relationship between the regularity of the permeability of single fractures in pore structure rocks to pore depth,the area of pores in the overlying water surface and fracture width.Then,based on the field investigation,the typical pore basalt rock was obtained and tested,and explore the permeability of the rock of different typical pore structures,obtain permeability of basalt foundations with different fracture characteristics.Finally,the research results of permeability pores basalt foundation are applied to the design of Yangshan Avenue drainage ditches in Haikou.And optimize the design based on the study of unpaved drainage ditches.Summarize the design values of the cross-sectional area of the unpaved drainage ditch under different gap widths with different columnar joints.