🌧️ Stormwater Detention Tunnel — городское ливневое

Модуль #304. Алматы 2024 наводнение Тысячелетие (350 м³/с peak) → план мегатоннеля ливневой канализации под город (cathedral-style TBM Robbins Ø8 м × 12 км под главными бульварами). Reference: Tokyo G-Cans Underground Discharge Channel (50 м H × 177 м wide × 5 chambers underground), Hong Kong WHHDS, London Lee Tunnel + Thames Tideway, Chicago TARP (175 mi tunnels). Detention buffers stormwater peak до treatment plant capacity 50-100 м³/с, prevents flooding city + combined sewer overflow CSO. ASCE Stormwater BMP + EPA Best Practices + СНиП 2.04.03.

1. Состав detention tunnel Ø8 м × 10 км

TBM Tunnel Boring Machine: Robbins EPB Ø8.5 м внутренний rotating cutter head + slurry support, 1500 кВт + tail shield + segment installer, скорость 10-15 м/сут;
Pre-cast concrete segments: 6 segments/ring × 1.5 м length × 400 мм thick B45 W12 + reinforcement, gasket EPDM Sealtech B40 для watertightness;
Tunnel cross-section: Ø8 м internal diameter ⇒ flow area 50 м², capacity 300 м³/с при velocity 6 м/с (manning n=0.013 concrete);
Drop shafts: 15-20 vertical drop shafts Ø3-5 м H=40-60 м на каждом интерсекшн с street drains, energy dissipation vortex/spiral design ICOLD;
Inlet control structures: grit chambers + bar racks 50 мм mesh, debris removal перед tunnel inlet, mechanical raking;
Tunnel ventilation: exhaust fan stations Ø5 м axial fan × 4 шт + intake shafts, для prevent buildup H2S при stagnant water (sewer integrated);
Storage capacity: 10 km × 50 м² × 0.8 useable = 400 000 м³ live storage (для 4-hour 100-year storm event);
Pump station discharge: 12 vertical pumps Sulzer SMD 25 000 м³/час × 30 м H + VFD ABB, total capacity 100 м³/с к treatment plant;
Treatment-grade effluent: screening + grit removal + sand filter + UV disinfection для combined sewer storm overflow;
Pump station building: ж/б underground 50×30×15 м с emergency egress shafts;
Manhole access: 30-50 vertical access shafts Ø4 м H=40 м для maintenance + inspection;
Cathodic protection: ICCP MMO-аноды на reinforcement bars (corrosion от sulfides);
Real-time monitoring: level sensors каждые 200 м + flow meters Endress+Hauser Promag + CCTV cameras 100 шт, integrated в city SCADA;
Hydraulic model: InfoWorks ICM software для real-time storm tracking + automatic gate operations;
Sustainability/Green Infrastructure: integration с green roofs + permeable pavement + bio-retention swales для reduce inflow.

Упражнение 1 — Tunnel vs surface stormwater

Surface канавы — дешевлеТолько дренаж под дорогамиPumping вездеDetention tunnel Ø8 м для megacity dense urban + climate change extreme rainfall: (1) capacity 400 000 м³ buffer vs surface канавы 5-10 м³/100 м, (2) hydrosphere буферирует 100-year storm event (350 м³/с Алматы 2024) распределяя на 4-12 часов discharge к WWTP @ 50-100 м³/с, (3) underground = no surface land use conflict в city centre, (4) gravity flow + minimal pumping, (5) combined sewer overflow CSO prevention важно для combined sewer system (хотя Алматы separated), (6) TBM Robbins построение быстрее open-cut 5-7x, (7) maintained service life 100+ лет ж/б B45 W12 + ICCP. Reference Tokyo G-Cans + Chicago TARP + London Thames Tideway. ASCE Stormwater BMP + EPA Best Practices

Упражнение 2 — Объём storage

Tunnel Ø8 м × 10 км. Useable fraction 70% (gravity flow + air gap). Объём (м³)?

Упражнение 3 — Капекс tunnel

TBM Robbins EPB Ø8.5 м lease + boring 10 км × 1.5 млрд тг/км = 15 млрд
Pre-cast segments B45 W12 + gasket = 2.2 млрд
Drop shafts 20 × Ø3-5 м H=50 м = 1.8 млрд
Pump station 12× Sulzer SMD 25 000 м³/ч + ВНС underground = 1.4 млрд
Ventilation fans + manholes + access shafts = 0.6 млрд
SCADA + InfoWorks ICM + monitoring = 0.4 млрд
Cathodic protection ICCP + проектирование 5% + ПИР + PNR + страхование = 0.6 млрд

Упражнение 4 — H2S corrosion

Никакой проблемыТолько концентрация oxygen controlH2S corrosion + sulfide aggression — sewer concrete corrosion: (1) stagnant water в tunnel anaerobic conditions → sulfate-reducing bacteria SRB Desulfovibrio convert SO4²⁻ → H2S, (2) H2S oxidises на crown ceiling concrete → H2SO4 sulfuric acid attack pH<1 → spalling 5-10 mm/year, (3) prevention measures: (a) high-density B45 W12 SS-resistant calcium aluminate cement liner Calcia / Densit 10-20 mm crown coating, (b) sodium hypochlorite NaOCl injection 1-2 mg/L при low-flow для oxidising H2S, (c) iron salts FeCl2 dosing для precipitating sulfide as FeS, (d) forced ventilation fans reduce H2S accumulation, (e) cathodic protection ICCP на reinforcement bars; ACI 313 + ASCE MOP 60 + WEF Sewer System Asset ManagementПросто заменять трубы

Нормативная база

ASCE Stormwater BMP Standards
EPA Stormwater Management Best Practices
ACI 313 — Standard Concrete Pipe
ASCE MOP 60 — Gravity Sanitary Sewer Design
WEF Sewer System Asset Management
СНиП 2.04.03-85 — Канализация наружные сети
СН РК 4.01-03 — Канализационные ОС
InfoWorks ICM — Hydraulic modeling software