1  General Provisions

1.0.1  This Regulation was develped for the purpose of safety and usability, environmental protection, advanced technology, economy and reasonablity and quality guarantee in the design and construction of building excavations.
1.0.2  This Regulation is applicable to the investigation, design, construction and detection of temporary construction excavations support as well as the excavations excavation and monitor under general geological conditions. This Regulation shall be applied in combination with local engineering experience as for rock excavations and such special soil as collapsible soil, permafrost, expansive soil and salty soil.
1.0.3  The excavations support design, construction and excavations excavation shall take such following factors into consideration as geological conditions, surroundings around excavations requirements, main part underground structure requirements, construction seasons change and support structure service life in accordance with local conditions for reasonable type selection, optimal design, careful construction and strict monitor and control.
1.0.4  Excavations supporting engineering shall comply with those specified in current relevant standards of the nation except the requirements of this Regulation.

2  Terms and Symbols

2.1  Terms
2.1.1  Excavations
 It refers to the space to be excavated downward from the ground for the construction of underground part of buildings (structures).
2.1.2  Surroundings around excavations
 The general term for the surrounding buildings (structures), underground pipelines, roads, rock-soil mass and groundwater body in mutual influence with excavation.
2.1.3  Retaining and protection for excavations
 Measures taken for temporary retaining, reinforcement, protection and groundwater control adopted for excavation to protect the safety of underground main structure construction and surroundings around excavation. 
2.1.4  Retaining and protection structure
 Retaining or reinforcing the structure of the excavation side wall.
2.1.5  Design workable life
 It refers to the period (specified in the design) from the excavation start to predetermined depth to fulfillment of excavation use function.
2.1.6  Retaining structure
 The support structure mainly based on structural member for earth retaining and anchor or support or only mainly based on structural member for earth retaining.
2.1.7  Anchored retaining structure
 Retaining structure mainly based on structural member for earth retaining and anchor.
2.1.8  Strutted retaining structure 
 Retaining structure based on structural member for earth retaining and bracing.
2.1.9  Cantilever retaining structure
 The retaining component only mainly based on structural member for earth retaining.
2.1.10  Structural member for earth retaining
 The retaining component arranged on side wall of excavation implanted into excavation bottom, i.e. support pile and diaphragm wall.
2.1.11  Soldier pile wall
 Retaining component component or cantilever retaining structure composed by support pile and capping beam arranged along excavation side wall.
2.1.12  Double-row-piles wall
 The retaining structure composed by rigid frame and capping beam connected by the two front and back rows of support piles and beams arranged along the excavation.
2.1.13  Diaphragm wall 
 It refers to the continous underground wall formed by special machinery groove forming and reinforced concrete pouring with groove segment, which may be referred to as cast-in-place diaphragm wall.
2.1.14  Anchor
 The tension member with one end composed by bolt body (steel strand, prestressed twisted steel reinforcement, ordinary steel bar or steel pipe), jet-grouted solid, anchor and sleeve connected with support structure member and the other end anchored in the stable rock-soil mass. It may be referred to as anchored cable where the steel strand is adopted for bolt body.
2.1.15  Strut
 The structural component (arranged in excavation) composed by reinforced concrete or steel member in order to support retaining component. Where steel and concrete are adopted for supporting members, they are respectively referred to as steel strut and concrete strut.
2.1.16  Capping beam
 Reinforced concrete beam (arranged at the top of retaining component) integrating the structural member for earth retaining.
2.1.17  Waling
 Reinforced concrete beam or steel beam (arranged at the side of structural member for earth retaining) connecting anchor or strut member bar.
2.1.18  Soil nail
 The member bar (implanted in the soil and formed by grouting bearing tensile force and shear force. For example, the steel bar soil nail composed by steel bar bolt body and jet-grouted solid and steel pipe soil nail hit into the soil.
2.1.19  Soil nailing wall
 The retaining and protection structure composed of soil nail group, sprayed concrete surface layer and in-situ soil mass arranged with excavation layering and densely-spread longitudinally and horizontally. 
2.1.20  Composite soil nailing wall 
 Composite retaining and protection structure composed of soil nail wall and one or more of the following: pressured anchor bolt, micropile, jet grouting pile and mixing pile.
2.1.21  Gravity soil-cement wall
 Gravity support structure of grilling or entity mutually overlapped by soil-cement columns.
2.1.22  Groundwater control 
 Such measures as interception, dewatering, drainage or recharge adopted to guarantee the normal construction of support structure, excavation and underground structure and provent the influence of underground water change on surroundings around excavation.
2.1.23  Curtain for cutting off drains
 It refers to curtain wall vertical water interception body to obstruct or decrease underground water from flowing into excavation through excavation side wall and excavation bottom and control groundwater lowering outside excavation.
2.1.24  Closed curtain for cutting off drains
 It refers to the curtain for cutting off drains with bottom end penetrating aquifer and entering the bottom aquiclude to certain detpth.
2.1.25  Unclosed curtain for cutting off drains
It refers to the curtain for cutting off drains with bottom not penetratingaquifer.
2.1.26  Dewatering
 It refers to the method to lower the underground water level inside and outside the excavation with pumping well or seepage well to prevent underground water from flowing into excavation through excavation side wall and excavation bottom.
2.1.27  Open pumping 
 The method to discharge the surface water and seepage water outside the excavation with the drainage system composed of drainage ditch, collector well, drain pipe and water pipe.