Design Drawing of Expansive Soil for Expressway Subgrade

Notes: 1. The dimensions in this drawing are in cm. 2. In order to facilitate the maintenance and repair of deep cut slopes, high embankment slopes, bridge abutments and other sections after construction and road access, maintenance steps shall be set on the slopes, which shall be built with M7.5 mortar rubble, and the surface shall be plastered with M7.5 cement mortar. 3. One maintenance step shall be set every 100m in the high embankment section, which shall be set in a staggered manner. One maintenance step shall be set on the embankment 10~15m in front and behind the bridgehead (tail) section. 4. When the maintenance step is set on the deep excavation slope, the step is set on the gentle natural hillside on both sides of the slope and connected with each level of platform. ...... The drawing contains: section view of high embankment, bridge abutment maintenance steps, elevation view of excavation maintenance steps, plan view of maintenance steps, bill of quantities per linear meter...... 1 piece in total

1. Unless otherwise specified, all dimensions in the drawing are in cm. 2. This drawing is applicable to the excavation slope covering seriously weathered rock mass, developed joints, soft rock, loose crushed (gravel) stone soil. 3. In addition to its own weight, the facing wall does not bear other loads, nor does it bear the earth pressure behind the wall. 4. Set a 2cm wide expansion joint (settlement joint) every 10-15m along the wall body, and fill it with asphalt hemp tendons, 10-20cm deep. When there is groundwater seepage on the slope, the drain holes should be properly densified. The drain holes should be staggered, with a spacing of 2-3 meters and a size of 10 × 10 cm; The drain hole in the figure is schematic. 5. When the wall height is within 3 ≤ H ＜ 6m, a ear wall is set at the wall back; When H ≥ 6m, two ear walls are set at the back of the wall, and the width of the ear wall is 50cm. 6. A 15cm gravel cushion is set at the back of the wall as the inverted filter. 7. When the height of the facing wall exceeds 10m, the top width is 60cm. 8. The quantities in the table do not include the quantities of platform intercepting ditches. 9. The construction of lining arch shall be coordinated with the laying of horizontal drainage pipes on the road shoulder and pavement. All joints must be strictly sealed without water permeability. 10. The lining arch column drainage channel corresponds to the upper channel, and the platform drainage channel is consistent with the berm channel. ...... Drawings include: elevation of solid facing wall slope protection, bill of quantities per linear meter, elevation of arch skeleton grassing slope protection, bill of quantities, section of arch column drainage ditch, three-dimensional vegetation network plan, U-shaped steel nail detail, bill of quantities per hundred meters (one side) Square Timber Pile Detail Cutting 3D Vegetation Network Profile Direct Spraying Grass Planting Slope Protection Plan Direct Spraying Grass Planting Slope Protection Profile Separate Subgrade Embankment Slope Width Design 3D Vegetation Network Plan 3D Vegetation Network Profile Lining Arch Skeleton Grass Planting Slope Protection Elevation Slope Protection Drainage Channel Plan...... 6 in total Zhang

The retaining wall body of expansive soil (rock) cutting expansive soil (rock) cutting shall be constructed with C20 rubble concrete, and the amount of rubble shall not exceed 20%. An expansion joint with a width of 0.02m shall be set every 10~15m along the line of the wall body, and asphalt hemp bars with a depth of not less than 0.2m shall be filled along the wall top, inside and outside of the joint. A φ 0.1m PVC pipe drain hole is set every 2m at 0.55m above the side ditch platform. The inverted filter layer of sand mixed with crushed stone with a thickness of 0.5m is set at the full length of the wall back. The lower part of the lowest drainage hole shall be provided with a compacted clay aquiclude not less than 0.3m thick; If there is no platform on the top of the wall, a compacted clay aquiclude shall be set within 0.5m from the top of the wall. The concrete cover of longitudinal load-bearing reinforcement of anchor pile shall not be less than 7cm. The joints of longitudinal load-bearing reinforcement shall be welded joints. Within 35d of the joints, the area of load-bearing reinforcement with joints shall not be greater than 50% of the area of reinforcement in this section. The number of reinforcement in this drawing does not include overlapping and loss. φ 0.05mPVC pipe shall be embedded around the pre reinforced anchor pile as a nondestructive testing hole to facilitate engineering quality testing. ...... 2 sheets in total, designed in 2010

Highway grade: design speed of expressway: 80km/h; width of integral subgrade: 24.5m; number of lanes: two-way four lane design is used for filling sections with thin soft soil and relatively good physical and mechanical indicators of soil layer. This is the layout of cement mixing pile (wet method) treatment for general fill subgrade section. It is applicable to subgrade with soft soil thickness greater than 3.0m. Layout of settlement observation pipe and displacement side pile for soft soil subgrade. Karst subgrade treatment plan...... 10 sheets in total

Design basis: Technical Rules for Design and Construction of Gob Roads (JTG/T D31-03-2011); Code for Geological Investigation of Highway Engineering (JTG C20-2011); Detailed Rules for Design of Highway Tunnel (JTG/T D70-2010)

Overview: design load: highway Class I. Profile: the maximum longitudinal slope is 5%, the minimum slope length is 200m, the minimum radius of convex vertical curve is 4500m, and the minimum diameter of concave vertical curve is 3000m. The minimum radius of horizontal curve limit is 250m, and the minimum radius is 400m. Cross section: highway grade: two-way four lane expressway; Design speed 80km/h; Subgrade width: integral 24.5m, separate 12.25m; The median is 3m wide and the median is 2m wide. The cross slope of roadway and hard shoulder crown is generally 2%, and that of soil shoulder crown is 4%.

Pavement drainage:

Normal road section: (1) the excavated road section is drained from the shoulder by the natural overflow of the road arch and through the side ditch; (2) The pavement water in the fill section flows naturally from the crown to the earth shoulder, and then flows into the drainage ditch along the slope; Ultra high road section: A. Extra high outer side (1) Cut road section and fill road section with slope height H ≤ 2m, pavement water is discharged through longitudinal drainage ditch; (2) For filling sections with slope height H>2m, a water collecting well and a horizontal drainage pipe are set at the left edge of the median, and the water flows into the drainage ditch through the chute. B、 The drainage method for the inner side of superelevation is the same as that for the normal road section. Central separation strip drainage (internal): composed of longitudinal seepage ditch, impervious layer and catch basin, and horizontal PVC drainage pipe. Horizontal drainage must be set from the lowest point of drainage longitudinal slope elevation; At the bottom of the concave vertical curve, in addition to the horizontal drainage at the lowest point, the horizontal drainage shall be added at the front and back 5m respectively.

Subgrade drainage:

It is composed of side ditch, intercepting ditch and drainage ditch. At the junction of filling and excavation, the side ditch flow is guided by the chute into the drainage ditch or ditch and other drainage outlets.

...... 27 sheets in total, designed in 2014

Notes: 1. All dimensions in the drawing are in cm, except for the wall height in m. 2. The retaining wall body and foundation are poured with C20 rubble concrete, and the content of rubble in the rubble concrete is not more than 20% of the wall volume. The retaining wall shall be made of hard rock that is not easy to be weathered. The strength grade of the rubble used shall not be less than MU40, and the thickness shall not be less than 15cm. 3. The foundation of the retaining wall shall be buried no less than 0.25m below the freezing line. The depth of the end of the retaining wall embedded in the original stratum of the cutting shall be no less than 1.5m for soil stratum, 1.0m for weathered rock stratum and 0.5m for slightly weathered rock stratum. When the retaining wall foundation is set on a stable and hard rock slope foundation, the foundation can be made into a step shape. The height width ratio of the step should not be greater than 2, and the width of the step should not be less than 0.5m. 4. The settlement expansion joint of the retaining wall shall be set every 10~15m. For the retaining wall of the integral wall body on the rock foundation, the joint spacing can be appropriately extended, but should not be greater than 25m. The settlement expansion joint is 2~3cm wide, and the joint is filled with asphalt oakum or asphalt coated wood along the inner, outer and top sides of the retaining wall, and the filling depth is not less than 15cm. 5. The spacing of the drain holes is 2m, and they are arranged in a quincunx shape staggered from top to bottom, left to right. φ 10cm PVC drainage pipes are embedded in the holes. The PVC pipes should be 10~20cm beyond the back of the structure. The end 50cm long should be set with φ 1cm round holes and wrapped with double-layer permeable geotextile. The lowest drain hole shall be 0.3m higher than the ground, or 0.6m higher than the bottom of the ditch. A 30cm thick crushed gravel inverted filter shall be set at the back of the wall. The pipe outlet must be lower than the water inlet and set at a slope of 4%. 6. The allowable bearing capacity of the retaining wall foundation base is shown in the table. If the bearing capacity of the excavated foundation base fails to meet the design requirements, please report to the design department in time. When the allowable bearing capacity is less than 250Kpa, the foundation bearing capacity should be calculated as 250Kpa. 7. When the concrete strength of the retaining wall reaches more than 70% of the design strength, it can be filled and compacted in layers to ensure the stability of the wall body. The backfill of retaining wall foundation pit shall be filled and compacted in layers, and the compactness shall not be less than 92%. 8. A 50cm (or 100cm) platform shall be reserved at the back of the wall according to the geological conditions to prevent the excavation of the retaining wall from causing the collapse of the upper slope. ...... The drawing contains: Section dimension table of structural design drawing of inclined cutting wall...... 1 sheet in total