The core of a smooth rubber dam overflow relies on these five key steps: high-precision leveling of the base plate, pre-leveling of the dam bags, symmetrical anchoring, precise control of filling and draining, and smooth energy dissipation downstream. This ensures that after dam collapse, the bags adhere tightly to the base plate without wrinkles or bulges.

I. Base Plate: Absolutely Flat (Root Cause)

Flatness: ≤ ±2～3mm with a 2m straightedge, no sharp edges, no protrusions, no pitting (epoxy mortar repair).
Anchoring Groove: Centerline deviation ≤ ±2mm, groove bottom ≤ ±1mm, ensuring smooth and fitted edges of the dam bag.
Surface Treatment: High-pressure grouting, smooth grinding, application of special primer, preventing localized high points from lifting the dam bag.

II. Dam Bag Installation: Pre-tensioning + Wrinkle-Free (Key)

Expanding and Leveling: Laser control of longitudinal height difference ≤ 5mm, transverse height difference ≤ 3mm, wooden wedges to smooth wrinkles.
Pre-tensioning: Pre-tensioning 1.5% along the length direction to completely eliminate loose wrinkles.
Symmetrical Anchoring: From the middle to both ends, downstream first then upstream, bolts are tightened evenly in three stages (40% 70% 100% torque) to prevent bulging caused by uneven tightness.
Edge and Corner Treatment: "Ω" fold with the side wall + stainless steel pressure strip sealing, no warped edges or corners.

III. Inflation and Drainage Control: Synchronous and Uniform (Dynamically Smooth)

Multiple Inlet and Outlet Inflation/Drainage: Multiple inlets and outlets are installed along the dam length for simultaneous and equal inflation/drainage, avoiding localized expansion/collapse that could cause a wave-like pattern.
Slow Pressure Reduction: During dam collapse, pressure is released slowly and the dam is emptied in stages, allowing the dam bags to spread gradually and evenly, preventing overturning or stacking.
Segmented Balancing: The long dam is divided into multiple independently controlled sections with consistent water levels between sections, eliminating elevation differences and steps.

IV. Downstream Energy Dissipation and Protection: Smooth Connection

Energy Stilling Basin + Apron: A concrete energy stilling basin, apron, and apron are installed downstream, smoothly connecting to the riverbed to prevent drops and eddies from lifting the dam bags.
Riverbed Smoothness: After dam collapse, the top surface of the dam bags is at the same elevation and slope as the upstream and downstream riverbeds, without abrupt changes or ledges.

V. Daily Maintenance: Long-Term Smoothness

Regularly check the flatness of the base plate, the torque of the anchor bolts, and the wear of the dam bags, promptly repairing bulges, wrinkles, and delamination.
There should be a trash rack installed upstream to prevent sharp objects from scratching the dam bag and causing local deformation.