Experimental study on the influence of uneven settlement of loess foundation on cast-in-place pipe gallery
The uneven settlement of collapsible loess foundation after immersion will cause additional internal forces to the cast-in-place pipe gallery structure,resulting in cracking or even destruction of the pipe gallery structure,which seriously threatens its operation safety.In order to further study the influence of collapsible deformation of loess stratum on cast-in-place pipe gallery,a model test of local immersion collapsible loess stratum was carried out.In the test,the local immersion range was set,and the depth of foundation immersion was used as a variable to monitor the bottom displacement,soil contact pressure,surface strain and surface settlement of the pipe gallery structure,and its development trend was analyzed.The test results show that when the immersion depth of the local basement reaches 20 cm,the tunnel structure has obvious bending deformation in the immersion area,and the maximum subsidence of the structure in the collapsible area reaches 0.57 mm.The area where the contact pressure between the structure and the soil changes greatly is the bottom plate of the pipe gallery at the edge of the collapsible area.When uneven settlement occurs in the local immersion at the bottom of the pipe gallery,the stress form of the structure is that the floor is pulled and the roof is pressed,and the farther away from the middle of the pipe gallery,the smaller the strain is,and the tensile and compressive strain changes at the edge of the collapsible zone.The surface subsidence phenomenon also occurs,and the maximum settlement value is 2.24 mm.The test results of this paper can provide reference for the design of cast-in-place pipe gallery in collapsible loess area and the prevention and control of related disasters.
cast-in-place pipe gallerycollapsible loesswater immersion collapsibilityfoundation settlementlaw of deformation
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