Method for deformation control of large-span tunnel in chlorite schist stratum
AssigneeChang'an Univeristy
InventorsJianxun Chen, Lijun Chen, Yanbin Luo, Pei Huang, Chaoxuan Zhang, Mengen Qin
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Abstract
A method for deformation control of large-span tunnel in chlorite schist stratum. The method divides the large deformation of large-span tunnel in chlorite schist stratum into five deformation grades according to the surrounding rock conditions of the tunnel. In response to each deformation grade, the deformation control of large-span tunnel is determined so as to ensure the safety and stability of the tunnel support structure and to avoid the clearance intrusion caused by tunnel deformation.
Claims9
A method for deformation control of large-span tunnel in chlorite schist stratum, comprising;
- dividing a deformation of a large-span tunnel in chlorite schist stratum into five deformation grades according to surrounding rock conditions of the tunnel, wherein the five large deformation grades are extremely serious large-deformation, serious large-deformation, medium large-deformation, slight large-deformation, and zero large-deformation;
- and
- controlling a deformation of the large-span tunnel corresponding to one of the five deformation grades,
- wherein the extremely serious large-deformation comprises the tunnel surrounding rock being composed of single chlorite schist, having a saturated uniaxial compressive strength Rc<5 MPa, and being in a powder or granular structure;
- wherein the serious large-deformation comprises the tunnel surrounding rock being composed of chlorite schist and contains 20% of quartz veins, containing underground water, having a saturated uniaxial compressive strength Rc of rock mass of 5-10 MPa, and having a rock mass integrity coefficient Kv≤0.15, and being in a cataclastic or granular structure;
- wherein the medium large-deformation comprises the tunnel surrounding rock being composed of chlorite schist and containing less than 20% quartz veins, having no underground water, having a saturated uniaxial compressive strength Rc of rock mass of 10-20 MPa, having a rock mass integrity coefficient Kv of 0.15-0.35, and being in a thin stratified structure with a layer thickness less than 10 cm or a cataclastic structure;
- wherein the slight large-deformation comprises the tunnel surrounding rock being composed of chlorite schist and containing large quartz veins with particle size greater than 5 cm, having no underground water, having a saturated uniaxial compressive strength Rc of rock mass of 20-25 MPa, having a rock mass integrity coefficient Kv of 0.35-0.55, and being in a thick stratified structure with a layer thickness greater than 10 cm or a blocky structure;
- and
- wherein the zero large-deformation comprises the tunnel surrounding rock being chlorite albite schist or other stratum with chlorite as a main part, having no underground water, having a saturated uniaxial compressive strength Rc of rock mass of equal or greater than 25 MPa, having a rock mass integrity coefficient Kv of 0.55-0.75, and being in a blocky structure.
Dependencies are inferred from the claim text.